Gastrointestinal System
Welcome to The Gastrointestinal System module. In this module, you will first review the anatomy and physiology of the stomach and the small and large intestines. You will then learn about medications that treat disorders of the gastrointestinal system, including peptic ulcers, constipation, diarrhea, irritable bowel syndrome, and inflammatory bowel disease.
Learning Objectives
Describe the structures and functions of the gastrointestinal system.
Identify medications and their expected actions used to treat a variety of disorders affecting the gastrointestinal system.
Explain the adverse reactions, contraindications, and interactions associated with medications used to treat a variety of gastrointestinal disorders.
Describe instructions the nurse should provide to clients receiving medications to treat a variety of gastrointestinal disorders.
Apply the nursing process related to medication therapy used to treat gastrointestinal disorders.
Anatomy and Physiology of the Gastrointestinal Tract
Anatomy and Physiology of the Gastrointestinal Tract
Video Transcript
Anatomy and Physiology of the Stomach
If you looked inside an empty stomach, you would see a lot of folded tissue called rugae. The mucosal and submucosal layers of the stomach make up these folds, which allow the stomach to expand in relation to the amount of food ingested. The mucosal layer of the stomach secretes a layer of mucus, which protects the inner layers of the stomach from hydrochloric acid and pepsin produced to aid digestion. The submucosal layer is connective tissue. It contains the structures that produce mucus, stomach acid, and pepsin, as well as some bicarbonate, which keeps the acid at the proper pH. The muscle and serosal layers wrap around the stomach, helping it to contract and propel chyme. The duodenum produces secretin, which stimulates the pancreas to produce bicarbonate and cholecystokinin. Cholecystokinin stimulates the gallbladder to release bile, an alkaline substance, into the duodenum, neutralizing the acidity of the chyme as it leaves the stomach. Additional enzymes produced by the pancreas and bile from the gallbladder enter the duodenum through their respective ducts and continue to break down the chyme into its smallest elements.
Gastrointestinal Motility
Gastrointestinal Motility
Video Transcript
Goal of Medication Therapy for Gastrointestinal Disorders
The goal of medication therapy for gastrointestinal disorders is to treat peptic ulcers, nausea, constipation, diarrhea, irritable bowel syndrome, and inflammatory bowel disease.There are seven categories of medications that support the treatment of peptic ulcers. They are histamine H2 antagonists, proton pump inhibitors, mucosal protectants, antacids, prostaglandin E analogs, antibiotics, and potassium-competitive acid blockers (P-CAB). Peptic ulcers are erosive lesions that occur in the stomach and duodenum. Lesions that are severe and involve several layers of the stomach can cause bleeding and even perforation. Typically, there is a balance between the production of gastric acid and protective mucus. Ulcers occur when this balance is disturbed, and gastric acid can penetrate the protective layer of mucus. One factor that contributes to this imbalance is an infection with bacteria called Helicobacter pylori.
Continue to the next page to begin the lesson. Histamine H2 Antagonists
Histamine H2 antagonists treat gastric and duodenal ulcers, heartburn and dyspepsia, gastrointestinal reflux disease, also called GERD, and aspiration pneumonitis. Histamine H2 antagonists also treat hypersecretory disorders such as Zollinger-Ellison syndrome, which causes increased production of gastrin, and systemic mastocytosis, which causes increased production of histamine.
Prototype and Other Medications
Cimetidine – Classification: Histamine (H2) Antagonist
The prototype medication for histamine H2 antagonists is cimetidine. Other medications in this category include famotidine and nizatidine.
Expected Pharmacologic Action
Histamine H2 antagonists block the histamine receptors in the stomach that are responsible for the secretion of stomach acid. They block the receptors located on the parietal cells in the stomach, decreasing the amount of stomach acid produced, and increasing the pH of stomach acid.
Adverse Drug Reactions
Impotence, gynecomastia, and reduced libido are side effects of cimetidine. Although not common, confusion, arrhythmias, agranulocytosis, and aplastic anemia may occur. There is an increased chance of clients contracting pneumonia related to the elevated gastric pH, allowing bacteria to colonize in the stomach, with a secondary increase in the respiratory tract.
Interventions
For clients who report impotence, reduced libido, or CNS effects, recommend they discuss this with their health care provider. Assess older clients for confusion as well as those with altered mental function.
Administration
Give histamine H2 antagonists orally, intramuscularly, or intravenously. Give them with or without food because there is no difference in absorption; however, given with meals, directly after, and at bedtime prolongs effects. Administer intravenous preparations slowly to avoid bradycardia. Do not give antacids within 1 hr of administration due to the potential for decreased absorption of the H2 antagonist. Make sure clients dissolve effervescent tablets in water and do not chew them, swallow them whole, or allow them to dissolve on the tongue.
Client Instructions
Instruct clients who are taking a histamine H2 antagonist to take all medication as prescribed even if manifestations have decreased. Smoking can affect the actions of this medication, so it should be avoided. Clients should be advised to avoid any products such as alcohol, aspirin, or NSAIDs that could increase GI irritation.
Contraindications and Precautions
Histamine H2 antagonists are contraindicated in anyone with a known sensitivity to the medication. Use this medication with caution for older adults (may require lower dosages) and for clients with kidney or liver dysfunction.
Interactions
Antacids can reduce the absorption of histamine H2 antagonists. Histamine H2 antagonists and other medications that decrease gastric acidity can decrease the absorption of azoles (itraconazole, ketoconazole). Cimetidine increases levels of warfarin, phenytoin, lidocaine, and theophylline.
Safety Alert
Cimetidine can increase serum levels of warfarin, an anticoagulant, which can lengthen clotting time beyond that which is safe. It can also increase the serum level of phenytoin, a medication to control seizures, to a toxic level with dangerous neurological side effects. And administering cimetidine with theophylline, a bronchodilator for respiratory disorders, can cause overstimulation of the heart, lungs, and central nervous system.Proton Pump Inhibitors (PPI)
Proton pump inhibitors also prevent and treat gastric and duodenal ulcers, prolonged dyspepsia, gastrointestinal reflux disease, or GERD, erosive esophagitis, and hypersecretory disorders such as Zollinger-Ellison syndrome and systemic mastocytosis.
Prototype and Other Medications
Omeprazole – Medication Classification: Prototype Proton Pump Inhibitor
The prototype proton pump inhibitor for this module is omeprazole. Other medications in this category are pantoprazole, lansoprazole, esomeprazole, and dexlansoprazole.
Expected Pharmacologic Action
Proton pump inhibitors inhibit the hydrogen potassium ATPase enzyme system in the parietal cells of the stomach. Inhibiting this enzyme system suppresses gastric acid production, both the basal rate that the stomach constantly produces, as well as the extra acid it produces secondary to the ingestion of food.
Adverse Drug Reactions
Clients who take proton pump inhibitors on a long-term basis are at an increased risk for bone loss. Some clients may experience headaches, abdominal pain, nausea, vomiting, and diarrhea while using proton pump inhibitors. Hypomagnesemia can occur in clients taking the medication for longer than 3 months, so it is advisable to monitor magnesium levels periodically during treatment.
Safety Alert
A client can safely take omeprazole for up to 8 weeks at a time. Medication therapy not effective within that time frame may be an indication that the provider needs to prescribe a different medication. The risk for osteoporosis increases with the length of therapy. The risk of osteoporosis increases due to decreased absorption of calcium secondary to a decrease in gastric acid. Clients on long-term therapy should ingest adequate amounts of calcium and vitamin D in either their diet or as supplements. Clients on long-term therapy may also need to supplement hypomagnesemia through oral magnesium supplements. Clients are at risk of rebound acid hypersecretion when stopping this medication, and it should be maintained at the lowest dose possible for the shortest time needed to achieve the desired effects. Recent studies have found a relationship between PPIs and Clostridium difficile (C. diff) infection, so any diarrhea should be immediately reported to the provider.
Interventions
When caring for clients who are taking a proton pump inhibitor, consider the dose and length of time a client is on the medication since it should be given at the lowest dose and for the shortest possible duration. When clients take a proton pump inhibitor for longer-term therapy, monitor for bone loss with bone density scanning at recommended intervals, as well as monitoring magnesium levels.
Administration
Proton pump inhibitors should be administered orally once a day before the first meal of the day. Make sure clients do not crush, chew, or break delayed-release capsules of omeprazole.
Client Instructions
Instruct clients taking proton pump inhibitors to perform weight-bearing exercises daily, as well as to consume adequate amounts of calcium and vitamin D to prevent bone loss. Clients should report severe vomiting or diarrhea to the provider and drink plenty of clear fluids. Remind clients to monitor magnesium levels during therapy.
Contraindications and Precautions
Clients should not take this medication if they have demonstrated a previous hypersensitivity to the medication as well as with clients concurrently taking rilpivirine. Use omeprazole with caution for clients who have liver dysfunction and for clients who are pregnant and lactating.
Interactions
Do not give omeprazole with atazanavir, ketoconazole, and itraconazole due to decreased absorption of these medications. Similar to cimetidine, levels of warfarin and phenytoin can increase when given these medications with omeprazole. Serum levels of diazepam can also increase. Food can reduce the absorption of omeprazole. St. John’s wort can decrease medication levels of omeprazole. Mucosal Protectants
Use mucosal protectants to treat acute duodenal ulcers.
Prototype and Other Medications
Sucralfate – Medication Classification: Mucosal Protectant
The prototype mucosal protectant you will learn about in this module is sucralfate.
Expected Pharmacologic Action
Sucralfate causes a chemical reaction to occur in the stomach, creating a gel that coats ulcers and creates a barrier between the stomach and gastric secretions.
Adverse Drug Reactions
Sucralfate is well tolerated but may cause constipation in a small percentage of clients. It is not absorbed, so the possibility of systemic effects is eliminated.
Interventions
Care for clients taking sucralfate includes monitoring bowel function and administering stool softeners as needed.
Administration
Administer sucralfate orally on an empty stomach. Give it four times a day, 1 hr before the usual three mealtimes and again at bedtime. Do not give it within 30 min of antacids. Avoid giving it within 2 hr of administering fluoroquinolone antibiotics, warfarin, phenytoin, theophylline, digoxin, tetracycline, or diazepam.
Safety Alert
Sucralfate can decrease the absorption of certain medications. Complete absorption of some of these medications is critical to maintain their therapeutic effects. Administer sucralfate 2 hr before or after medications such as warfarin, phenytoin, and digoxin, whose serum levels are vital for their therapeutic effects.
Client Instructions
Instruct clients prescribed sucralfate to increase their fluid and fiber intake, as well as activity and exercise, to prevent constipation. Be sure the client knows to drink plenty of fluids if diarrhea occurs, and if it becomes severe, to report it to the provider. Tell clients to report any manifestations of obvious or occult gastrointestinal bleeding, such as coffee-ground-appearing emesis.
Contraindications and Precautions
Sucralfate is contraindicated for clients who have a hypersensitivity to the medication. Use it with caution in clients who have renal failure, diabetes, or difficulty swallowing.
Interactions
Sucralfate decreases the absorption of fluoroquinolone antibiotics. It also decreases the absorption of tetracycline, as well as digoxin, warfarin, phenytoin, theophylline, and diazepam. Antacids reduce the therapeutic effects of sucralfate. Antacids
Use antacids to treat peptic ulcer disease (PUD) and gastrointestinal reflux disease, commonly abbreviated as GERD.
Prototype and Other Medications
Aluminum hydroxide – Medication Classification: Antacid
The prototype medication for antacids is aluminum hydroxide. This antacid is aluminum-based. Two other types of antacids are magnesium-based antacids and calcium-based antacids. An example of a magnesium-based antacid is magnesium hydroxide, also called “milk of magnesia,” and an example of a calcium-based antacid is calcium carbonate. One compound combines magnesium and aluminum hydroxide.
Expected Pharmacologic Action
Antacids are alkaline compounds that neutralize gastric acid.
Adverse Drug Reactions
Side effects of antacids include constipation when clients take aluminum and calcium antacids and diarrhea when clients take magnesium antacids. That is why clients often take magnesium antacids as a laxative to treat constipation or combined with an aluminum antacid, which causes constipation. Together they minimize both types of effects. Hypophosphatemia can occur with antacids that contain aluminum due to its ability to bind with phosphate, decreasing its absorption.
Interventions
When caring for clients on an antacid, monitor bowel function for constipation or diarrhea, depending on the type of antacid. If clients are taking an antacid that causes constipation, administer stool softeners as needed. When giving an aluminum-based antacid, monitor clients’ phosphorus levels.
Administration
Give antacids orally and up to four times a day. Make sure clients chew the tablets thoroughly, followed by a full glass (8 oz) of water. Clients should drink water after taking liquid preparations. Do not give antacids within 1 to 2 hr of administering medications that interact with antacids. Aluminum hydroxide should be administered 1 to 3 hr after meals and at bedtime.
Client Instructions
Instruct clients to take an aluminum- or calcium-based antacid to increase their fluid and fiber intake, as well as their activity and exercise levels. Emphasize the need to report abdominal pain and diarrhea if the client takes a magnesium-based antacid. Due to the risk of hypophosphatemia, clients should be instructed to monitor phosphorous and sodium intake. Tell clients to report any manifestations of obvious or occult gastrointestinal bleeding, such as coffee-ground emesis, which could mean their ulcer disease is worsening.
Contraindications and Precautions
Contraindications to the use of antacids include severe abdominal pain of unknown origin. Use antacids with caution for clients with hypercalcemia and hypophosphatemia.
Interactions
Antacids decrease the absorption of many medications, including tetracyclines, digoxin, fluoroquinolones, iron salts, salicylates, and chlorpromazine, so should not be administered within 1 to 2 hr of taking other medications.
Safety Alert
Since antacids can affect the absorption of many medications, plan administration around the times that other medications are being given. Administer antacids 1 to 2 hr before or after all other medications. Avoiding concurrent administration of an antacid with any medication ensures that potential medication interactions do not occur.Prostaglandin E Analog
Use prostaglandin E analogs to prevent gastric ulcers that can result from long-term use of non-steroidal anti-inflammatory drugs, or NSAIDs.
Prototype and Other Medications
Misoprostol – Medication Classification: Prostaglandin E Analog
The prototype medication for prostaglandin E analog medications is misoprostol.
Expected Pharmacologic Action
Misoprostol is an endogenous prostaglandin. It decreases gastric acid secretion, increases secretion of bicarbonate, which is a base, increases secretion of protective mucus in the stomach, and increases vasodilation of submucosal blood flow in the gastric wall, which provides the tissue with an adequate supply of blood.
Adverse Drug Reactions
The primary adverse reactions of misoprostol are diarrhea and abdominal pain. Because misoprostol is a prostaglandin, it can also cause spontaneous abortion, spotting, uterine cramps, and dysmenorrhea, or painful menstruation.
Interventions
When caring for clients who are taking misoprostol, monitor for severe diarrhea and abdominal pain. Monitor clients who take misoprostol for excessive menstrual pain or mid-cycle bleeding, known as spotting.
Administration
Administer misoprostol orally four times a day, with each meal, and again at bedtime while the client is on NSAID therapy. Confirm that clients are not pregnant before initiating medication therapy, as this medication can cause spontaneous abortion. Make sure clients who are able to become pregnant use an effective form of contraception during medication therapy.
Safety Alert
Misoprostol is a prostaglandin analog that can stimulate uterine contractions. This can cause a spontaneous abortion during early pregnancy and premature labor later in pregnancy. If a client who is able to become pregnant is unsure whether they are pregnant, they should take a pregnancy test prior to starting the medication. Review the need for using a reliable method of birth control and provide oral and written information about the risks of taking misoprostol during pregnancy.
Client Instructions
Tell clients taking misoprostol to report worsening diarrhea or abdominal pain. They should expect diarrhea to resolve after the first week of medication therapy. If they drink plenty of fluids during this time, it will minimize the risk of dehydration. If necessary, clients can take the medication with food to minimize gastrointestinal effects. Finally, tell clients to report menstrual changes such as spotting, painful menses, and any postmenopausal bleeding. Instruct clients to avoid ingesting alcohol or any foods that may irritate the GI tract while taking misoprostol.
Contraindications and Precautions
Do not give misoprostol to a pregnant client because it has teratogenic effects. Taking this medication while pregnant could result in a spontaneous abortion. It can be therapeutically administered to clients who are pregnant prior to induction of labor to soften the cervix and stimulate uterine contractions under supervised medical conditions. Do not give it to clients with a demonstrated hypersensitivity to the medication. Use misoprostol cautiously for children younger than 18 years of age. Antibiotics
Clients diagnosed with peptic ulcers and who test positive for the presence of the bacteria, Helicobacter pylori, also called H. pylori, are treated with antibiotics. Since Helicobacter pylori is a gram-negative bacillus, the antibiotics that treat this infection include clarithromycin, amoxicillin, metronidazole, and tetracycline. Refer to the Infection module for additional information about these medications. Updated guidelines for treating H. pylori include using at least two antibiotics, in conjunction with an antisecretory agent, to minimize medication resistance and to achieve the best outcomes. Potassium-Competitive Acid Blockers (P-CABs)
Potassium-competitive acid blockers (PCABs)
Prototype and Other Medications
Vonoprazan – Classification: Potassium-Competitive Acid Blocker (PCAB)
The prototype P-CAB medication is vonoprazan, which is given as part of a combination package with one or more antibiotic medications for the treatment of peptic ulcers caused by H. pylori.
Expected Pharmacologic Action
Potassium-competitive acid blockers act on gastric parietal cells to prevent acidity by decreasing proton pump secretions. Differences between P-CABs and PPIs are that P-CABs are not enteric coated, so they do not need to be taken 30 min before meals, and because they act immediately on the proton pump, they have a more rapid onset of action than PPIs.
Adverse Drug Reactions
Adverse drug reactions may result from vonoprazan or from the antibiotics that are given as part of dual or triple therapy. The most common adverse effects of the combination therapy are diarrhea, disturbances in taste, vaginal yeast infection, abdominal pain, headache, hypertension, and nasopharyngitis.
Interventions
Before a client begins therapy with vonoprazan in combination with antibiotics in a triple package or dual package, assess for allergies to penicillin, macrolides, and cephalosporins.
Administration
Vonoprazan is a tablet that is combined as a triple pack with amoxicillin and clarithromycin or as a dual pack with amoxicillin. The medication is taken twice daily (every 12 hr), with or without food, for 14 days.
Client Instructions
If a client misses a dose, they should take the medication as soon as possible, up to 4 hr past the scheduled time. If the dose is more than 4 hr late, the client should skip that dose and resume taking the medication at the next scheduled time. Because the medication package includes antibiotic medication, the client should be educated on the importance of taking the medication for the full 14 days as prescribed to maximize the effectiveness of the treatment and to prevent antibiotic resistance from developing.
Contraindications and Precautions
Triple therapy that includes clarithromycin is contraindicated for clients who have a prolonged QT interval, ventricular arrhythmias, hypokalemia, hypomagnesemia, or bradycardia or who are taking other medications that may prolong the QT interval. Triple therapy is contraindicated for clients who are also taking pimozide, lipid-lowering agents, and ergot alkaloids and clients who have decreased renal or hepatic function and are taking colchicine.
Triple- or dual-packaged products with vonoprazan and antibiotics should only be administered to clients who have bacterial infections to prevent the development of antibiotic resistance.
Safety Alert
Clients who are allergic to penicillin or other beta-lactam medications should not be prescribed the dual or triple therapy combination. Clients who are allergic to clarithromycin should not be prescribed the triple therapy combination.
Interactions
The triple therapy combination may alter the effectiveness and increase the risks for adverse effects if taken concurrently with antivirals, itraconazole, antiarrhythmics, colchicine, antipsychotics, omeprazole, benzodiazepines, hypoglycemics, and statins. The dual therapy combination may alter the effectiveness and increase the risks for adverse effects if taken concurrently with antivirals, anticoagulants, and immunosuppressants.Antiemetics are the medications known to relieve nausea and vomiting. There are several classifications, including serotonin 5-HT3 antagonists, antihistamines (anticholinergics), and dopamine antagonists, that will be further discussed in this module. Other classifications include glucocorticoids, cannabinoids, substance P/neurokinin antagonists, and benzodiazepines. Serotonin 5-HT3 Antagonists
Use serotonin 5-HT3 antagonists to treat nausea and vomiting that occurs secondary to chemotherapy and radiation therapy and during the postoperative recovery period.
Prototype and Other Medications
Ondansetron – Medication Classification: Serotonin 5-HT3 Antagonists
The prototype medication for serotonin 5-HT3 antagonists is ondansetron. Other medications in this category are granisetron and palonosetron.
Expected Pharmacologic Action
Serotonin 5-HT3 antagonists block 5-HT3 (5-hydroxytryptamine-3) serotonin receptors located in the chemoreceptor trigger zone in the brain, abbreviated CTZ, and on the nerve terminals of the afferent vagal nerves that innervate the stomach and small intestine. When the medication antagonizes 5-HT3 serotonin at these sites, it minimizes nausea and subsequent vomiting.
Adverse Drug Reactions
Adverse drug reactions include serotonin syndrome, torsade de pointes, and Stevens-Johnson syndrome. Common adverse reactions of serotonin 5-HT3 antagonists are generally mild, such as headache, dizziness, constipation, and diarrhea.
Interventions
When caring for clients taking a serotonin antagonist for nausea or vomiting, monitor for headache and report to the provider if a client is experiencing severe or persistent headaches. Administer analgesics for relief of mild headaches. When ambulating clients taking a serotonin antagonist, monitor for dizziness and provide safety measures as needed. If diarrhea occurs, monitor its severity and watch for manifestations of dehydration.
Administration
Serotonin 5-HT3 antagonists can be given orally or intravenously. When treating chemotherapy-induced nausea and vomiting, give the medication intravenously and slowly over a period of 15 min, starting 30 min before chemotherapy, and then give the medication 4 to 8 hr later. When treating anesthesia-induced nausea and vomiting, give the medication 1 hr before the induction of anesthesia, postoperative, and then every 8 hr as needed. When treating radiation-induced nausea and vomiting, give the medication orally 1 to 2 hr prior to radiation therapy, then every 8 hr as needed.
Client Instructions
Instruct clients who are self-administering serotonin 5-HT3 antagonists to report severe or persistent headaches. Recommend taking over-the-counter analgesics to relieve a headache. Tell clients to report dizziness and avoid engaging in dangerous activities if dizziness occurs or tends to recur. During episodes of dizziness, clients should lie down and change positions slowly. If diarrhea occurs, clients should monitor its severity, drink plenty of fluids, and watch for manifestations of dehydration. Notify the provider for diarrhea that becomes severe or persistent.
Safety Alert
Dizziness can cause clients to have difficulty with their balance, making the risk of falls great. Dizziness can also be aggravated by quick movements of the head and riding in a vehicle. Instruct clients who are experiencing dizziness secondary to ondansetron to change positions slowly and to lie down if it is severe. Remind clients to call for the nurse prior to ambulating to the restroom to ensure safety and keep furniture and care-related items out of the client’s path to the hall and restroom. If clients continue taking ondansetron at home, instruct them to avoid driving and operating any kind of mechanical devices that could cause injury.
Contraindications and Precautions
Do not give to clients with known hypersensitivity. Oral disintegrating tablets of ondansetron should not be used in clients with phenylketonuria. Likewise, it should not be used concurrently with apomorphine or when there is congenital long QT syndrome. Use with caution in clients who have hepatic disease, recent abdominal surgery, or in clients who are pregnant or lactating, or in children younger than 3 years old.
Interactions
Medications that affect serotonergic neurotransmitter systems, including SSRIs, SNRIs, tricyclic antidepressants, MAOIs, fentanyl, lithium, buspirone, tramadol, methylene blue, and triptans increase the risk of serotonin syndrome. Concurrent use with apomorphine increases the risk of loss of consciousness and severe hypotension.Antihistamines/Anticholinergics
Antihistamines can be given for their antiemetic effects, as well as their ability to counteract the vertigo that accompanies motion sickness.
Prototype and Other Medications
Dimenhydrinate – Medication Classification: Antihistamine
Dimenhydrinate is one of the antihistamines that has antiemetic and antivertigo effects.
Expected Pharmacologic Action
Antihistamines prevent vertigo, nausea, and vomiting by blocking the release of histamine H1 receptors in the inner ear, as well as those related to the neurons that connect the inner ear to the chemoreceptor trigger zone, or CTZ.
Adverse Drug Reactions
Adverse effects of antihistamines include sedation and drowsiness, as well as dizziness, and the anticholinergic effects of dry mouth, constipation, and urinary retention.
Interventions
Due to the sedating effects of antihistamines, monitor clients when they’re ambulating. To combat the anticholinergic effects of dry mouth, encourage clients to take frequent sips of water or suck on hard candy. To combat the anticholinergic effect of constipation, recommend high-fiber foods and provide a fiber supplement or laxative as needed. Monitor for urinary retention, especially in older men who have urinary hesitancy or enlargement of the prostate gland. Monitor pulse and BP when administering antihistamines via IV route, both prior to and throughout therapy. Assess for allergic reactions such as pruritus, rhinitis, and hives. When using to treat nausea or motion sickness, assess amount, frequency, and degree of emesis.
Safety Alert
Men who are older and have an enlarged prostate are at greater risk for urinary retention secondary to antihistamines. Antihistamines decrease the tone of the bladder, making complete emptying difficult when an enlarged prostate is pressing on the urethra. A high residual, which is the amount of urine left in the bladder after emptying, can increase a client’s risk for a bladder infection. Keeping strict intake and output can alert of an intake that is significantly higher than output. If retention is suspected, use an ultrasound machine to scan the bladder immediately after voiding to determine the amount of urine that is being retained.
Administration
Give dimenhydrinate orally or intramuscularly for vertigo or nausea. Give the initial dose 30 to 60 min before the activity that triggers nausea. Give the other doses before meals and at bedtime. Tell clients not to swallow chewable tablets whole. Dimenhydrinate can be administered 50 to 100 mg (PO, IM, IV) every 4 to 6 hr PRN for motion sickness or activities that manifest as nausea.
Client Instructions
Instruct clients prescribed an antihistamine to avoid taking it prior to driving or activities requiring mental alertness. Tell them to sit or lie down if they are feeling drowsy. Explain that changing positions gradually will decrease their risk of falls. For dry mouth, tell clients to suck on hard candy or chew gum and to take frequent sips of water. For constipation, tell clients to increase their fluid and fiber intake and increase activity levels as tolerated. Recommend they urinate every 4 hr and report any undesirable changes in urinary elimination.
Contraindications and Precautions
Antihistamines are contraindicated for clients who have known hypersensitivity, angle-closure glaucoma, and premature or newborn infants. Use with caution in older adult clients, as well as clients who have hyperthyroidism, cardiovascular disease, hepatic disease, pyloric obstruction, prostatic hypertrophy, and in clients who are pregnant or lactating.
Interactions
If giving antihistamines with other CNS depressants, it will cause increased sedative effects. If giving MAO inhibitor antidepressants concurrently, it will increase anticholinergic effects.Dopamine Antagonists/Prokinetic Agents
Dopamine antagonist medications, also called prokinetic agents, are the final category in relation to the treatment of nausea to be discussed in this module. Dopamine antagonist medications are effective in treating nausea and vomiting associated with chemotherapy, opioids, and radiation therapy. They can also be used to increase GI motility in conditions such as gastroesophageal reflux and diabetic gastroparesis.
Prototype and Other Medications
Metoclopramide – Medication Classification: Prokinetic/Antiemetic
Metoclopramide is the prototype dopamine antagonist/prokinetic medication.
Expected Pharmacologic Action
Metoclopramide is a dopamine receptor blocker. It’s effective against GERD because it increases tone of the lower esophageal sphincter. It is effective against diabetic gastroparesis because it increases peristalsis in both the stomach and intestines. It effectively treats nausea and vomiting because it increases the threshold of the chemoreceptor trigger zone in the brain, also called the CTZ.
Adverse Drug Reactions
Metoclopramide can cause sedation, extrapyramidal reactions, restlessness, and neuroleptic malignant syndrome. Due to the increased rate of the propulsion of food through the gastrointestinal tract, diarrhea is also an adverse effect. Extrapyramidal manifestations, consistent with the uncontrollable, repetitive movements of tardive dyskinesia, may occur when a client takes metoclopramide on a long-term basis or in high doses. Extrapyramidal effects may be irreversible.
Interventions
Monitor clients receiving metoclopramide when they are ambulating due to its sedative effects. If a client experiences diarrhea, monitor its severity and watch for the development of dehydration. Recommend the lowest possible dose for the shortest duration of time due to the possibility of irreversible extrapyramidal effects. In the meantime, monitor for restlessness, anxiety, spasms of the face and neck, lip smacking, writhing motions, and involuntary movements. If any of these occur, discontinue the medication and notify the provider. Assess clients for manifestations of neuroleptic malignant syndrome such as muscle rigidity, hyperthermia, tachycardia, diaphoresis, and altered consciousness.
Administration
Give metoclopramide orally, intramuscularly, or intravenously. When treating chemotherapy-induced nausea and vomiting with large doses, infuse the medication intravenously and slowly over 15 to 30 min, starting 30 min before chemotherapy is administered. The amount to be administered IV is 1 to 2 mg/kg initially, with additional doses of 1 to 2 mg/kg given every 2 to 4 hr. Administering a pretreatment with diphenhydramine will decrease the risk of extrapyramidal reactions. When administering metoclopramide for other GI disorders, administer doses of 10 mg or less intravenously over 1 to 2 min or give oral forms 30 min before meals and at bedtime.
Client Instructions
Tell clients not to take metoclopramide prior to driving or engaging in other activities that require mental alertness. Tell the client to sit or lie down if they feel drowsy. Remind clients that changing positions gradually will help prevent falls. Instruct clients to report diarrhea and to drink plenty of fluids. Reinforce the need to immediately report restlessness, anxiety, or spasms of the face and neck, lip smacking, writhing motions, and involuntary movements.
Contraindications and Precautions
Metoclopramide is contraindicated for clients who have gastrointestinal obstruction, hemorrhage, perforation, an uncontrolled seizure disorder, pheochromocytoma, or breast cancer. Use it with caution for older adults and clients who have heart failure, hypertension, asthma, Parkinson’s disease, hypokalemia, porphyria, seizure disorders, and liver or kidney dysfunction.
Safety Alert
Metoclopramide often treats functional gastrointestinal obstructions, including paralytic ileus, a condition in which peristalsis of the small bowel stops. The use of metoclopramide with a mechanical obstruction, such as a tumor or twisted bowel, can cause severe pain and even intestinal rupture. Be sure the cause of an intestinal obstruction is determined before administering metoclopramide to clients who have a bowel obstruction.
Interactions
If using CNS depressants concurrently with metoclopramide, it will increase metoclopramide’s sedative effects. If given metoclopramide with opioids and anticholinergics, it will decrease metoclopramide’s therapeutic effects on the gastrointestinal tract. Giving metoclopramide with a phenothiazine medication that can also cause extrapyramidal effects will worsen these types of manifestations. And metoclopramide can negatively affect the absorption of many medications, including acetaminophen, aspirin, diazepam, tetracycline, digoxin, and lithium. There are several types of medications for the treatment of constipation, including osmotic laxatives, bulk-forming agents (fiber supplements), surfactant laxatives, also referred to as stool softeners, and stimulant laxatives. Osmotic Laxatives
Prototype and Other Medications
Polyethylene glycol (PEG) – Medication Classification: Osmotic Laxative
The prototype osmotic laxative is polyethylene glycol. Other examples include magnesium citrate, sodium phosphate, and saccharide laxatives (lactulose, sorbitol).
Expected Pharmacologic Action
Osmotic laxatives, or laxative salts, draw water into the intestines, resulting in the enlargement and softening of the fecal mass. This leads to increased peristalsis and can, dependent upon dosage, produce bowel evacuation within 2 to 12 hr.
Adverse Drug Reactions
Common adverse reactions include diarrhea, electrolyte imbalances, nausea, cramping, and flatulence.
Interventions
The powder form of PEG should be completely mixed with 4 to 8 oz of water, juice, or other liquids. Monitor client for improvements in stool consistency and frequency and decreased straining with bowel movements.
Administration
Some osmotic laxatives are available without a prescription. Polyethylene glycol is an oral solution that is administered once daily for constipation for a maximum of 7 days. The medication may be a premixed solution or a powder that is dissolved in liquid. High dosages of these laxatives are reserved for bowel prep prior to surgical or diagnostic procedures.
Client Instructions
Clients should be instructed to contact their provider if they experience diarrhea, rectal bleeding, or other GI bleeding or if the osmotic laxative is needed for longer than 1 week.
Contraindications and Precautions
Contraindications include bowel obstruction, and a client who has findings consistent with bowel perforation, acute abdomen, or toxic megacolon should be assessed before PEG is administered. Clients who have renal disease should not use PEG without consulting their provider.
Safety Alert
For clients who have dysphagia, PEG cannot be thickened with starch-based thickeners since aspiration may occur.
Interactions
Concurrent use of osmotic laxatives with stimulant laxatives may cause ulcerations and ischemia of the intestines. Renal impairments and fluid and electrolyte imbalances may occur if a client is using osmotic laxatives and loop diuretics concurrently.Bulk-Forming Agents/Fiber Supplements
In a nutrition course, students learn how important it is to include fiber in their diet. Fiber is used to counteract the side effects of constipation for many of the medications already discussed. So, it should not be a surprise that fiber supplements can be used to treat constipation. Also, use fiber supplements to prevent and treat diverticulosis, as well as irritable bowel syndrome. Fiber can also help regulate stools for clients who have a fecal ostomy and are experiencing diarrhea.
Prototype and Other Medications
Psyllium – Medication Classification: Bulk-Forming Agents (Fiber Supplements) (Laxative)
There are several types of fiber supplements. The prototype medication for this group contains psyllium. Other types of fiber supplements contain calcium polycarbophil and methylcellulose.
Expected Pharmacologic Action
Fiber supplements are also called bulk-forming laxatives because they are non-digestible and absorb water from the intestine to form a glutinous mass that adds bulk to the stool. Added bulk or size of the stool will stretch the intestinal wall, stimulating peristalsis while softening and enlarging the fecal mass. A soft, formed stool is normally produced following 1 to 3 days of use.
Adverse Drug Reactions
Fiber supplements have few adverse effects since they are not absorbed. However, give them with a full glass of water or juice of water because esophageal or intestinal obstruction can occur.
Safety Alert
Fiber supplements swell and become viscous soon after they mix with a fluid. Clients who do not drink adequate amounts of fluid with a fiber supplement run the risk of it becoming a thick glutinous mass in their esophagus or intestine, creating a blockage. Be sure clients can drink 8 oz of fluid after taking a fiber supplement to ensure absorption of the proper amount of fluid.
Interventions
When supporting the care of clients taking a fiber supplement, emphasize that the client should take at least 8 oz of fluid with each dose. Monitor intake and output, as well as bowel function, to determine if a client is receiving an appropriate amount of the supplement. If diarrhea occurs, ensure that the client is receiving adequate fluids to prevent dehydration. Monitor for retrosternal pain, which could indicate the client is taking insufficient fluids with the medication, creating a glutinous mass in the esophagus.
Administration
Give fiber supplements orally 1 to 3 times a day with at least 8 oz of fluid. Mix powdered forms with 8 oz of fluid, and have the client drink them immediately. Tell clients that taking fiber supplements before meals might reduce their appetite. Monitor for and expect soft, formed stools 1 to 3 days after initiating therapy.
Client Instructions
Instruct clients on the proper administration of a fiber supplement. Tell them to take it with at least 8 oz of water or juice and to drink it immediately. Any delay will allow the supplement to gel in the glass, which makes it difficult to drink and unpalatable. Instruct clients to report difficulty swallowing, chest pain, or absence of bowel movements, as well as diarrhea. Remind them that the effectiveness of the supplement is dependent on drinking plenty of clear fluids. Finally, advise clients to increase exercise and fluid intake to at least 2 to 3 liters per day and to consume high-fiber foods such as bran, fresh fruits, and vegetables.
Contraindications and Precautions
Do not give fiber supplements to clients who have an esophageal or gastrointestinal obstruction, narrowing of the intestinal lumen, fecal impaction, dysphagia, nausea and vomiting, appendicitis, or undiagnosed abdominal pain.
Interactions
Psyllium impedes transit time through the GI tract and therefore can decrease the absorption of orally ingested medications.Surfactant Laxatives/Stool Softeners
Surfactant laxatives, or stool softeners, are another type of medication that treat constipation, as well as prevent fecal impaction, straining during defecation, and painful elimination of hard stools.
Prototype and Other Medications
Docusate sodium – Medication Classification: Stool Softener
The prototype medication for stool softeners is docusate sodium. Docusate sodium can be given in combination with senna, a stimulant laxative.
Expected Pharmacologic Action
Stool softeners are also called surfactant laxatives because they change the surface tension of the stool. By changing the surface tension, stool softeners increase the absorption of water into the stool. Stool softeners also act on the intestinal wall, which causes decreased absorption of fluids through it while increasing the secretion of water and electrolytes from the intestinal wall. When the stimulant laxative senna is added to docusate sodium, senna stimulates the intestinal motility of the colon and acts on the intestinal wall in much the same way that docusate sodium does. These activities produce a softer stool and enhance intestinal motility to facilitate passage of the stool.
Adverse Drug Reactions
The adverse effects of stool softeners are uncommon, but there have been cases of diarrhea, mild abdominal cramps, throat irritation, and rashes.
Interventions
Monitor clients taking a stool softener for abdominal distention and pattern of bowel function. Administer with a full glass of water or juice on an empty stomach for best results. Assess stool consistency, color, and amount.
Administration
Give stool softeners orally with at least 8 oz of fluid. Expect stools to be softer several days after initiating therapy.
Client Instructions
Instruct clients taking a stool softener to stop taking the medication if severe diarrhea occurs and to notify the provider. Remind clients to drink plenty of fluids when taking a stool softener, especially if they experience diarrhea. Finally, advise clients to increase exercise and fluid intake, to drink at least 2 to 3 L per day, and to consume high-fiber foods such as bran, fresh fruits, and vegetables.
Contraindications and Precautions
Stool softeners are contraindicated for clients who have gastrointestinal obstruction or perforation, fecal impaction, are experiencing nausea and vomiting, are also using mineral oil, or have undiagnosed abdominal pain. Use with caution in clients who are susceptible to developing a dependency on laxatives.
Interactions
Stool softeners should not be administered within 2 hr of any other laxative, especially mineral oil.Stimulant Laxatives
Give stimulant laxatives for constipation that results from opioid use or from slow intestinal transit time. You may also give them as part of a colon prep prior to elective procedures, such as a colonoscopy. Stimulant laxatives are often overused by clients and should be closely monitored.
Prototype and Other Medications
Bisacodyl – Medication Classification: Stimulant Laxatives
The prototype medication for stimulant laxatives is bisacodyl. There are many other types of stimulant laxatives, some of which are senna, which is derived from the senna plant; castor oil, which is derived from vegetable oil and the castor bean; and cascara sagrada, which is derived from the bark of an herb. Both senna and cascara sagrada contain compounds called anthraquinones.
Expected Pharmacologic Action
Stimulant laxatives stimulate the intestinal motility of the colon. They also act on the intestinal wall, causing decreased absorption of fluids through it while increasing the secretion of water and electrolytes from it.
Adverse Drug Reactions
Stimulant laxatives have more side effects than fiber supplements and stool softeners. They can cause diarrhea and mild abdominal cramps due to the increased transit time of waste through the colon. When giving them in suppository form, the client may feel a burning sensation. Prolonged use of suppositories can cause proctitis, an inflammation of the rectum. Long-term use of laxatives can result in misuse and dependence on them to have a bowel movement.
Interventions
Monitor clients who are taking a stimulant laxative for severe diarrhea and dehydration. The risk for this side effect is greater with stimulant laxatives than with fiber supplements or stool softeners. Warn clients receiving a bisacodyl suppository that rectal or anal burning may occur. Monitor for rectal discomfort, bleeding, or discharge of mucus or pus. Due to the potential for overuse, discourage long-term use of a stimulant laxative. Monitor bowel elimination pattern, along with intake and output.
Administration
Stimulant laxatives can be given orally or by rectal suppository. Expect a semi-fluid stool within 6 to 12 hr with oral dosing and 15 to 60 min with suppositories. Tell clients to delay taking the oral form at least 1 hr after drinking milk or taking antacids and not to crush or chew enteric-coated or delayed-release tablets. These medications should remain intact until they reach the colon.
Client Instructions
Instruct clients who take stimulant laxatives to report severe diarrhea and stop taking the medication. Remind them to drink plenty of fluids to prevent dehydration. Warn clients that taking bisacodyl by suppository causes a burning sensation. Reinforce the need to stop the medication and report rectal discomfort, bleeding, or discharge to the provider, as this may indicate proctitis. Due to the risk of misuse and dependence, reinforce the need to increase exercise and fluid intake to at least 2 to 3 L per day, and add high-fiber foods such as bran, fresh fruits, and vegetables instead of taking a stimulant laxative repeatedly.
Safety Alert
In today’s society, constipation is a very common and chronic problem due to diets low in fiber and reduced levels of activity. This is why many clients turn to laxatives as a means of promoting regular bowel movements. However, prolonged use of stimulant laxatives can cause the intestine to become sluggish and require higher and higher doses of laxatives to produce a bowel movement. Integrating dietary changes and exercise into a client’s lifestyle prevents laxative dependence from developing.
Contraindications and Precautions
Do not give stimulant laxatives to clients who have a gastrointestinal obstruction or perforation, anal or rectal fissures, ulcerated hemorrhoids, fecal impaction or ileus, proctitis, and undiagnosed abdominal pain, as well as clients who experience nausea and vomiting. Use them with caution in clients with eating disorders or other factors that increase the risk of overuse. Clients with eating disorders may take laxatives to rid their body of unwanted calories. However, laxatives actually promote loss of water instead of caloric-dense waste. This loss of water can contribute to bloating and constipation, creating a vicious cycle.
Interactions
Do not give stimulant laxatives concurrently with antacids or milk because they can dissolve the enteric coating, which is meant to dissolve in the colon, causing abdominal cramping. May decrease absorption of other oral medications because it decreases the time the medication stays in the intestinal tract – allow 1 hr time frame between this and other oral medications.The category of medications that supports the treatment of diarrhea discussed below is opioids. Probiotics will also be briefly discussed.Opioids
Constipation is a side effect of opioids, and this side effect is what makes opioids valuable in the treatment of diarrhea. Due to the decrease in the transit time of food, opioids are also valuable in reducing the volume of ileostomy effluent. An ileostomy is a waste removal orifice that is created when the colon is removed, and a loop of ileum is brought out through the wall of the abdomen. Effluent is the liquid discharge of feces. It is released in liquid form because, without the colon, water is no longer absorbed from the feces, leaving it in liquid form.
Prototype and Other Medications
Diphenoxylate with atropine and loperamide – Medication Classification: Anti-diarrheal
There are two prototype opioids for this category of medications. They are the prescription medication diphenoxylate with atropine and the over-the-counter medication loperamide.
Expected Pharmacologic Action
Opioids decrease intestinal peristalsis, which in turn increases transit time through the intestinal tract. This allows for increased absorption of water from the feces, resulting in smaller and harder feces as well as fewer bowel movements.
Adverse Drug Reactions
Adverse reactions of antidiarrheal opioids include cardiac arrest and cardiac arrhythmias. Other side effects include drowsiness and constipation. These effects are much more pronounced with diphenoxylate and atropine. Clients may experience anticholinergic effects such as dry mouth, especially clients taking diphenoxylate and atropine due to the side effects of atropine.
Interventions
Monitor clients who are taking an opioid for diarrhea when they ambulate in relation to the potential for sedation, dizziness, lightheadedness, and drowsiness. Recommend the lowest effective dose for the client and for the shortest period of time, as needed, to treat acute diarrhea. Monitor for anticholinergic effects, provide clients with gum and hard candy, and encourage sips of water for dry mouth. Monitor urinary elimination patterns for retention, especially in older adults.
Administration
Give opioids to treat diarrhea orally. Give up to 20 mg per day of diphenoxylate with atropine in 5 mg doses. Continue for 24 to 36 hr to determine its efficacy. Be aware that excessive doses of diphenoxylate with atropine can cause CNS effects similar to morphine, but atropine in high doses causes unpleasant effects that discourage misuse. In the rare instance of overdose, treat with naloxone.
Give an initial 4 mg dose of loperamide, and then follow each loose stool with an additional 2 mg, but do not exceed 16 mg per day. Stop loperamide after 48 hr if diarrhea persists. Be aware that loperamide is an analog of the opioid meperidine, but it is not a controlled substance, and even at high doses does not cause opioid effects or dependence.
Client Instructions
Instruct clients taking an opioid to avoid taking the medication before they drive or participate in activities that require mental alertness. Make sure they know to sit or lie down if they are feeling lightheaded. Recommend changing positions gradually to prevent falls. If clients experience dry mouth, recommend that they suck on hard candy, chew gum, or sip water. Encourage clients, especially older adults, to urinate every 4 hr and report any undesirable changes in urinary elimination.
Safety Alert
Clients experiencing persistent diarrhea are at risk for fluid and electrolyte imbalances. Be sure clients replace the fluids that are lost with water and/or commercial electrolyte solutions. They should also avoid caffeine because it has diuretic effects and can also increase the motility of the intestine, prolonging the diarrhea. Clients who do not see an improvement in the number and consistency of stools after 36 to 48 hr of loperamide or diphenoxylate therapy should consult their provider to determine the underlying cause.
Contraindications and Precautions
Do not use opioids to treat diarrhea in children younger than 2 years of age or clients who have advanced hepatic disease, glaucoma, severe fluid and electrolyte imbalance, pseudomembranous enterocolitis, diarrhea due to poisoning, ileus, or gastrointestinal bleeding. Use opioids with caution in clients who have inflammatory bowel disease, such as ulcerative colitis, renal or liver dysfunction, a history of chemical toxicity, and prostatic hypertrophy.
Interactions
If giving an opioid preparation, such as diphenoxylate, for diarrhea with other CNS depressants (alcohol, antihistamines, sedatives), it will increase CNS depression. If given with a monoamine oxidase inhibitor, it will increase the risk of hypertensive crisis. Concurrent use of cimetidine, erythromycin, and quinine may increase the risk of cardiac arrhythmias. Probiotics
Although probiotics are nutritional supplements and not FDA-approved medications, they are mentioned here because they are sometimes recommended by providers as part of the treatment of diarrhea from multiple causes, including antibiotic use, rotavirus, C. diff., H. pylori, irritable bowel syndrome, and ulcerative colitis. Probiotics can help restore the normal flora of the intestines that has been disrupted by diarrhea because they contain the same types of bacteria or yeasts that are present in the normal flora.
There are many strains of probiotics, including Lactobacillus and Bifidobacterium strains, and clients should consult with their provider for the appropriate type and dosage to restore the balance of normal flora for the condition being treated. Probiotics are available in various supplement forms (capsules, tablets) and food sources (yogurts, kefir).
Adverse effects of probiotics include nausea, bloating, abdominal pain, headache, and changes in appetite and frequency of stools.Irritable bowel syndrome (IBS) is a disorder that is more common in clients who were assigned female at birth and is characterized by cramping abdominal pain and either diarrhea, constipation, or a combination of both. The exact cause is unknown and may vary between clients. Some clients identify stress and specific foods as triggers. A combination of medication therapy and avoidance of offending foods can control the manifestations in most clients.
Medications have been approved to support the treatment of irritable bowel syndrome. Two of those medications, alosetron for IBS with diarrhea (IBS-D) and lubiprostone for IBS with constipation (IBS-C), will be discussed here. 5-HT3 Blocker
Give alosetron to treat severe irritable bowel syndrome with diarrhea in clients who were assigned female at birth only.
Prototype and Other Medications
Alosetron – Medication Classification: 5-HT3 Blocker
Alosetron is the prototype medication for this class. It is only approved to treat clients who were assigned female at birth who have IBS and diarrhea or IBS-D that has lasted more than 6 months and has not responded to conventional treatment. Another medication that is prescribed to treat IBS-D is eluxadoline, a mixed mu receptor agonist/kappa opioid receptor antagonist that is approved to treat clients who have IBS-D.
Expected Pharmacologic Action
Alosetron blocks serotonin 5-HT3 receptors. By blocking these receptors, it decreases visceral pain, slows peristalsis, increases absorption of water and sodium through the intestinal wall, and reduces the secretion of water and electrolytes from the intestinal wall.
Adverse Drug Reactions
The most significant adverse effect of alosetron is constipation, which can result in impaction, perforation, and even obstruction. Ischemic colitis is another related adverse effect that can contribute to intestinal injury and even death. In an effort to reduce potentially serious adverse reactions, clients must participate in a risk management program along with their provider and pharmacist while taking this medication.
Interventions
When caring for clients taking alosetron, closely monitor their bowel patterns. If constipation occurs, stop medication therapy until it resolves. Closely monitor for indications of ischemic colitis such as abdominal pain, bloody diarrhea, or rectal bleeding. For clients who develop any of these manifestations, stop the medication therapy immediately and notify the provider.
Safety Alert
Clients taking alosetron run a high risk of severe constipation and impaction if not closely monitoring them or if the dose of the medication is not adjusted accordingly. To accomplish this, keep track of the number of bowel movements a client has, as well as the consistency of those bowel movements. Prior to discharge, make sure clients are informed of the risks, that they know the side effects to report, and that they sign the required agreement for treatment with this medication.
Administration
When administering alosetron, make sure clients meet specific risk management criteria, and sign the required treatment agreement before administration. The risk management program provides guidelines for the client, provider, and pharmacist. It outlines potential adverse effects and criteria that must be met for treatment. It is only available for clients who were assigned female at birth and who did not improve with traditional therapies. Give alosetron orally twice daily. The initial dosage is usually 0.5 mg twice a day, and if well tolerated, it may be increased to 1 mg twice a day. If diarrhea persists after 8 weeks, stop therapy.
Client Instructions
Instruct clients prescribed alosetron to report constipation immediately and stop taking the medication. Clients should also report abdominal pain, bloody diarrhea, or rectal bleeding immediately and should discontinue taking the medication.
Contraindications and Precautions
Alosetron is contraindicated for clients who have chronic, severe, or complicated constipation, diverticulitis, Crohn’s disease, ulcerative or ischemic colitis, thrombophlebitis or another hypercoagulable state, toxic megacolon, and any type of gastrointestinal perforation, obstruction, or stricture. Use it with caution for older adults and clients who have renal or hepatic dysfunction.
Interactions
Alosetron levels may be altered by medications that interfere with cytochrome P450 enzymes, such as phenobarbital, carbamazepine, cimetidine, and quinolone antibiotics. Fluvoxamine, a medication that treats depression, increases alosetron levels.5-HT4 Receptor Agonist
Give lubiprostone for irritable bowel syndrome with constipation (IBS-C) in clients who were assigned female at birth and who are 18 years of age or older. Clients who were assigned male or female at birth and who are experiencing chronic idiopathic constipation (CIC) can also take lubiprostone.
Prototype and Other Medications
Lubiprostone – Medication Classification: 5-HT4 Receptor Agonist
Lubiprostone is the prototype medication for IBS-C and is approved for use in clients who were assigned female at birth and who are 18 years of age or older. Linaclotide is a guanylate cyclase agonist that is also approved for the treatment of clients who have IBS-C and CIC.
Expected Pharmacologic Action
Lubiprostone acts to decrease visceral pain, increase peristalsis, and increase the secretion of water and electrolytes from the intestinal wall. This activates chloride channels in the intestinal wall, which then increases the secretion of sodium and water.
Adverse Drug Reactions
Side effects of lubiprostone include nausea and vomiting, as well as diarrhea and flatulence. Clients may also experience headaches.
Interventions
Monitor for persistent nausea, vomiting, and diarrhea in clients taking lubiprostone. For clients who develop these indications, stop the medication therapy immediately and notify the provider. Monitor for headaches and provide a mild analgesic as needed.
Administration
Give lubiprostone orally as prescribed, which is usually twice a day, with food or water to minimize nausea. Make sure clients swallow the capsule whole. Do not administer the medication if the client is experiencing diarrhea.
Client Instructions
Instruct clients taking lubiprostone to take the medication with food or water. If nausea occurs, suggest the client lie down. Reinforce the need to notify the provider of severe vomiting, diarrhea, or abdominal pain. If these occur, the client should stop taking the medication and maintain hydration with clear fluids. Recommend that the client take over-the-counter analgesics to relieve headache and report persistent headaches to the provider.
Contraindications and Precautions
Lubiprostone is contraindicated for clients who have severe diarrhea; diverticulitis; Crohn’s disease; ulcerative colitis; volvulus, which is a bowel obstruction caused by a twisting of the bowel; and gastrointestinal obstruction. Use lubiprostone with caution when a client has any type of gastrointestinal disease.
Interactions
Synthetic opioids, such as methadone, may decrease the effectiveness of lubiprostone. Lubiprostone should not be administered to a client who is receiving lactulose for the treatment of hepatic encephalopathy.There are four categories of medications that support the treatment of inflammatory bowel disease, abbreviated IBD. They are 5-aminosalicylates, immunomodulators, immunosuppressants, and glucocorticoids. Antibiotics are also used in the treatment protocol for IBD – refer to the Infection module for more detailed information. IBD includes the disorders of Crohn’s disease and ulcerative colitis, both of which are characterized by inflammation of the intestinal tract. Crohn’s disease affects the entire intestinal tract, while ulcerative colitis affects only the colon. The inflammation that accompanies these disorders is believed to be due to an autoimmune response of the body. Autoimmune disorders are those in which a client’s antibodies attack their own tissue, resulting in inflammation. That is why the medications discussed in this section either suppress the immune response or prostaglandin synthesis, which in turn decreases inflammation. Because the Neurological System 1 module discusses immunomodulatory, and the Immune module discusses glucocorticoids, this module only addresses the categories of 5-aminosalicylates and immunosuppressants. 5-Aminosalicylates
Use 5-aminosalicylates to treat mild to moderate inflammatory bowel disease.
Prototype and Other Medications
Sulfasalazine – Medication Classification: Aminosalicylates
The prototype medication for the 5-aminosalicylates is sulfasalazine. Other medications in this category include mesalamine.
Expected Pharmacologic Action
Sulfasalazine is a sulfonamide antibiotic. It is converted in the intestine into two components: 5-aminosalicylic acid, also called b, and sulfapyridine. Mesalamine is a prostaglandin inhibitor that decreases inflammation in the intestines. Sulfapyridine provides no therapeutic effect for IBD and can actually cause adverse effects. Some clients take mesalamine alone instead of sulfasalazine to avoid the side effects caused by the sulfapyridine component of sulfasalazine.
Adverse Drug Reactions
Adverse effects of sulfasalazine include nausea, fever, rash, headaches, and hematologic disorders such as agranulocytosis and megaloblastic or hemolytic anemia.
Interventions
When caring for clients who are on sulfasalazine, monitor for worsening nausea, vomiting, or diarrhea. If nausea, vomiting, and/or diarrhea persists, notify the provider for a possible adjustment in dose, or change to an enteric-coated tablet. However, check the stools of clients taking an enteric-coated tablet for intact tablets to ensure that their body is capable of dissolving the enteric coating. Regularly monitor the client’s temperature and inspect for skin rash. Ask clients if they are experiencing any joint pain due to the potential for arthralgia. And finally, monitor clients’ CBC periodically for alterations in their white or red blood cell counts.
Administration
Sulfasalazine is available in oral form only. Mesalamine is available orally or as a local treatment in the form of a retention enema or suppository. Inspect stools for intact pills. If the client passes a medication in the stool intact, notify the provider for a possible change in the type of pill. It is not uncommon for enteric-coated pills to pass unchanged through the intestinal tract because the enteric coating did not dissolve, possibly due to a lack of a needed enzyme. When this happens, the provider should prescribe a non-enteric-coated pill. Make sure clients do not crush or chew the delayed-release tablets. Expect clients taking sulfasalazine to experience a change in urine and skin color.
Safety Alert
Sulfasalazine is a sulfonamide, which is a group of medications that contain sulfa. Clients who demonstrate an allergy to sulfa may also experience an allergic reaction to sulfasalazine. Clarify with the provider the existence of the client’s allergy to sulfa before giving this medication to a sensitive client. Mesalamine is an alternative medication that still contains the active ingredient of 5-aminosalicylic acid medications but without the addition of sulfonamide.
Client Instructions
Instruct clients taking sulfasalazine to take the medication with food or water to decrease gastrointestinal discomfort, and if the medication does cause nausea, recommend lying down until it passes. Tell clients to report vomiting, diarrhea, fever, or rash, as these may indicate sensitivity to the medication. As always, tell clients to drink plenty of clear fluids if vomiting, diarrhea, or fever occurs. Clients should report painful joints and take analgesics to relieve joint pain, along with getting rest. Emphasize the need to report sore throat, infections, fatigue, dyspnea, or dizziness that could indicate the development of a hematologic disorder. Clients should wear sunscreen and protective clothing when outdoors to prevent burning.
Contraindications and Precautions
Sulfasalazine is contraindicated for clients who are sensitive to salicylates, sulfonamides, or trimethoprim. Its use is also contraindicated for clients who have folate deficiency, megaloblastic anemia, agranulocytosis, renal failure, porphyria, and gastrointestinal or urinary tract obstruction. Use sulfasalazine with caution in older adults and in clients who have renal or hepatic dysfunction, a blood dyscrasia, asthma, or a glucose-6-phosphate dehydrogenase (G6PD) deficiency. This is an enzyme deficiency that affects the production of red blood cells. Should not be given to children who are less than 2 years old.
Interactions
If administered sulfasalazine with iron or antibiotics, it will affect the absorption of sulfasalazine. Administering mesalamine with digoxin will decrease the absorption of digoxin.Immunosuppressants
Immunosuppressants are another type of medication that is useful in treating IBD. While immunosuppressants are approved to prevent organ rejection and treat rheumatoid arthritis, their use to treat autoimmune disorders and IBD is considered an off-label use.
Prototype and Other Medications
Azathioprine – Medication Classification: Immunosuppressant
Azathioprine is the prototype medication for immunosuppressants. Other medications in this category include cyclosporine and methotrexate.
Expected Pharmacologic Action
Immunosuppressants inhibit the production of B and T lymphocytes, which in turn decreases the immune response in the body.
Adverse Drug Reactions
Adverse reactions of immunosuppressants include nausea, vomiting, anorexia, hepatotoxicity, fever, and bone marrow suppression, including neutropenia and thrombocytopenia.
Interventions
When caring for clients taking an immunosuppressant for IBD, monitor for and report persistent nausea, vomiting, and anorexia. Due to the risk for hepatitis, check liver function tests such as alanine transaminase (ALT), aspartate transaminase (AST), and alkaline phosphatase (ALP). Check clients’ complete blood count before initiating therapy and periodically thereafter. And if a client’s white blood count decreases, stop medication therapy and institute neutropenic precautions, which are measures that prevent the client from infectious agents.
Safety Alert
Clients who have a decreased WBC are at greater risk for infection. Implement neutropenic precautions with these clients. These precautions include handwashing, avoiding unnecessary invasive procedures such as injections, and providing meticulous care of wounds, catheters, and other equipment that breaks the natural barrier of the skin or can serve as a reservoir of infection. Restrict visitors and staff with an upper respiratory infection from entering the client’s room. Sometimes clients are also put on a special diet that does not allow ingestion of raw fruits or vegetables. Also, restrict live plants from the room of clients who are severely neutropenic. Closely monitor neutropenic clients for an increase in temperature. If one occurs, notify the provider immediately and be ready to institute intensive antimicrobial therapy.
Administration
Immunosuppressants can be given either orally or intravenously. Give oral forms with food to minimize gastrointestinal upset. Explain to the client that the onset of therapeutic effects may take up to 6 months.
Client Instructions
Instruct clients to take their oral immunosuppressant with food and to lie down if nausea occurs. Tell them to report severe vomiting, fever, abdominal pain, or jaundice to their provider. Reinforce that any of the following should be immediately reported to the provider: sore throat, infection, fatigue, dyspnea, dizziness, easy bruising, or bleeding.
Contraindications and Precautions
Do not give azathioprine to clients who have an active infection, pancreatitis, or anuria. Immunization with live virus vaccines is also contraindicated during azathioprine therapy. Clients who have myasthenia gravis or renal or hepatic dysfunction should only take azathioprine if the benefits outweigh the risks.
Interactions
If concurrently administering azathioprine and allopurinol, a medication for gout, it can increase blood levels of azathioprine. Antibiotics
Although the use of antibiotics increases the risk for developing IBS, some antibiotics, such as rifaximin (a derivative of rifampin), may be used as part of the treatment of IBS with diarrhea for clients who have pathogenic bacteria in the intestines. Antibiotics are discussed in the Infection lesson.