MODULE 5 NON-REDUNDANT

Digestive system problems

• Constipation = accumulation of hard fecal matter in the large intestine

• Nausea = queasy sensation that may or may not come before vomiting

• Vomiting = actual expulsion of gastric contents

• Diarrhea = frequent liquid stools

• Peptic ulcer = erosion occurring in the esophagus, stomach, or duodenum

Nausea and vomiting causes

• Motion sickness

• Viral and bacterial infections

• Food intolerance

• Surgery

• Pain

• Shock

• Selected drugs

• Radiation

• Middle-ear disturbances

Nausea and vomiting neurotransmitters

• Dopamine

• Acetylcholine

Non-pharmacologic measures for nausea/vomiting

• Give weak tea, flat soda, gelatin, Gatorade/Pedialyte, crackers, and dry toast

• Avoid oily foods and dairy

• Keep NPO if necessary

• Avoid identified triggers

• Maintain upright position

Antiemetics

• Used to prevent/treat nausea, vomiting, vertigo, and motion sickness • MOA = inhibit stimulation of the CTZ and vestibular pathways • Can mask the underlying cause of vomiting • Available OTC or by prescription

Non-prescription antiemetics

• Mainly used to prevent motion sickness

• Have minimal effect on severe vomiting

• Take about 30 minutes before traveling

• Examples = dimenhydrinate, cyclizine hydrochloride, meclizine hydrochloride, diphenhydramine hydrochloride

Bismuth subsalicylate

• Non-prescription antiemetic/antidiarrheal

• Available as liquid and chewable tablets

Phosphorated carbohydrate solution

• Hyperosmolar carbohydrate solution

• Acts by changing gastric pH

• High sugar content

• Do not give to patients with diabetes mellitus

Antiemetics during pregnancy

• Module says antiemetics are not recommended when possible

• Prefer non-pharmacologic measures such as ginger and red raspberry leaf tea

• When necessary = pyridoxine and doxylamine

• Severe vomiting = promethazine or metoclopramide

Prescription antiemetic categories

• Antihistamines

• Anticholinergics

• Dopamine antagonists

• Serotonin receptor antagonists

• Glucocorticoids

• Miscellaneous

Hydroxyzine

• Antihistamine used for postoperative nausea and vomiting

• Administer deep IM

• Side effects = drowsiness, dizziness, fatigue, ataxia, headache, blurred vision, dry mouth, urinary retention, constipation

Scopolamine

• Anticholinergic used for postoperative nausea/vomiting and motion sickness

• Apply patch to hairless area behind ear at least 4 hours before travel

• Alternate ears if used longer than 3 days

• Wash hands after application

• Wear only one patch at a time

• Side effects = dizziness, drowsiness, fatigue, headache, blurred vision, dry mouth

Dopamine antagonists

• Block dopamine receptors in the CTZ

• Extrapyramidal symptoms (EPS) are a common side effect

• Categories = phenothiazines, butyrophenones, benzodiazepines

Phenothiazines

• Dopamine antagonists used for nausea/vomiting from surgery, anesthetics, chemotherapy, and radiation sickness

• For cancer treatment, administer the night before, day of, and 24 hours after treatment

• Antiemetic dose is usually smaller than psychiatric-treatment dose

Chlorpromazine

• Phenothiazine dopamine antagonist • Used as an antiemetic for nausea and vomiting

Prochlorperazine edisylate

• Phenothiazine dopamine antagonist • Used as an antiemetic for nausea and vomiting

Promethazine

• Phenothiazine dopamine antagonist • Used for nausea/vomiting • Considered a high-alert medication (HAM) when given IV • Anticholinergic effects increase with antihistamines • Can interfere with urinary PT and cause false results • Can cause moderate sedation, hypotension, EPS, and CNS effects

Butyrophenones

• Dopamine antagonists used for postoperative nausea/vomiting associated with toxins, cancer chemotherapy, and radiation therapy

Droperidol

• Butyrophenone dopamine antagonist • Can cause EPS with extended use • Hypotension is a common side effect

Benzodiazepines as antiemetics

• Indirectly control nausea/vomiting associated with cancer chemotherapy • Lorazepam is preferred over diazepam • Best used with a glucocorticoid and serotonin receptor antagonist

Serotonin receptor antagonists

• Suppress nausea/vomiting by blocking serotonin receptors in the CTZ • Also block afferent vagal nerve terminals in the upper GI tract • Examples = ondansetron, granisetron, dolasetron, palonosetron

Palonosetron

• Serotonin receptor antagonist • Module identifies it as the most effective antiemetic for chemotherapy-induced nausea/vomiting • Does not cause EPS

Glucocorticoid antiemetics

• Suppress nausea and vomiting associated with chemotherapy • Examples = dexamethasone and betamethasone • Betamethasone may be given IV for a short period to minimize side effects

Dronabinol

• Cannabinoid used to relieve nausea/vomiting from cancer treatment • Active ingredient is related to cannabis • Only prescribed when other antiemetics do not work • Contraindicated in psychiatric patients • Side effects = mood changes, euphoria, drowsiness, dizziness, headache, depersonalization

Trimethobenzamide

• Miscellaneous antiemetic • Does not act strictly as an antihistamine, anticholinergic, or phenothiazine • Suppresses impulses to the CTZ

Metoclopramide

• Miscellaneous antiemetic • Suppresses emesis by blocking dopamine receptors in the CTZ • High doses can cause sedation and fatigue • EPS is more common in children than adults

Emetics

• Used to induce vomiting • Should NOT be given after ingestion of corrosive substances • Only given to an alert and conscious individual

Syrup of ipecac

• Emetic formerly used to induce vomiting • Module specifically states emetics should not be given to victims of corrosive-substance ingestion

Activated charcoal

• Module notes use after ingestion of corrosive substances • Used to adsorb certain substances in the GI tract

Diarrhea

• Frequent liquid stools • Causes = foods, fecal impaction, bacteria/viruses, toxins, drug reactions, laxative abuse, malabsorption syndrome, stress/anxiety, bowel tumor, inflammatory bowel disease • Risk = metabolic acidosis • Can be life-threatening because of fluid/electrolyte loss, especially in older adults

Non-pharmacologic measures for diarrhea

• Provide clear liquids • Prepare Oresol • Avoid oily foods and dairy products • Encourage BRAT diet for adults

Antidiarrheals

• Treat diarrhea and decrease intestinal hypermotility • Module says should not be given for more than 2 days or when fever is present • Main groups = opiates/opiate-related agents and adsorbents

Diphenoxylate with atropine

• Opiate-related antidiarrheal • Decreases intestinal motility/peristalsis • Less potential for drug dependence • Used for traveler’s diarrhea • Atropine decreases abdominal cramping, intestinal motility, and hypersecretion

Difenoxin with atropine

• Opiate-related antidiarrheal • Decreases intestinal motility/peristalsis • Drug dependence may occur with prolonged use • Used for nonspecific and chronic diarrhea • Atropine decreases abdominal cramping, intestinal motility, and hypersecretion

Loperamide

• Opiate-related antidiarrheal structurally related to diphenoxylate • Causes less CNS depression • Available OTC • Protects against diarrhea • Reduces fecal volume and intestinal fluid/electrolyte losses

Adsorbent antidiarrheals

• Coat the GI tract wall and adsorb bacteria or toxins causing diarrhea • Examples = kaolin/pectin and bismuth subsalicylate

Kaolin and pectin

• Adsorbent antidiarrheal • Used for mild to moderate diarrhea • Available OTC

Bismuth subsalicylate for diarrhea

• Adsorbent antidiarrheal • Used for traveler’s diarrhea • Available OTC • Side effects listed = dizziness, drowsiness, headache, tongue/stool discoloration, anxiety

Colestipol and cholestyramine

• Adsorbent/bile-acid binding drugs in the module • Used for diarrhea caused by excess bile acids in the colon

Constipation

• Accumulation of hard fecal matter in the large intestine • Common complaint and major problem in older adults • Causes = insufficient fluids, poor diet, fecal impaction, bowel obstruction, chronic laxative use, neurologic disorders, ignoring urge to defecate, lack of exercise, drugs

Non-pharmacologic measures for constipation

• Increase dietary fiber • Increase oral fluids • Exercise daily • Practice routine bowel habits

Laxatives vs cathartics

• Laxatives = promote soft stool with no cramping • Cathartics = promote soft to watery stool with some cramping

Laxative classifications

• Contact/stimulant or irritant • Chloride channel activators • Emollients/stool softeners • Bulk-forming • Osmotic/saline

Contact stimulant laxatives

• Irritate sensory nerve endings in intestinal mucosa • Increase peristalsis

Bisacodyl

• Contact/stimulant laxative • Frequently used and abused • Available OTC • Used to empty bowel before diagnostic tests • Oral onset = 6–8 hours • Suppository onset = 15–60 minutes

Castor oil

• Contact stimulant/purgative • Quick onset = 2–6 hours • Do not give at bedtime or during early pregnancy • Mainly used for bowel preparation

Contact laxative side effects

• Dizziness • Nausea • Abdominal cramps • Weakness • Reddish-brown urine

Chloride channel activators

• Activate chloride channels in small-intestinal lining • Increase intestinal fluid secretion and motility • Used for idiopathic constipation

Lubiprostone

• Chloride channel activator for idiopathic constipation • Contraindications listed = history of mechanical obstruction, Crohn disease, diverticulitis, severe diarrhea

Emollients/stool softeners

• Lubricants/surface-acting or wetting drugs • Lower surface tension and promote water accumulation in intestine/stool • Prevent constipation and decrease straining during defecation • Examples = docusate sodium, docusate calcium, docusate sodium + senna

Emollient contraindications

• Module lists contraindications = children, older adults, debilitating disease, pregnancy, appendicitis, ulcerative colitis, diverticulitis, spastic colon, bowel obstruction

Bulk-forming laxatives

• Natural fibrous substances • Absorb water in intestine • Increase fecal bulk and peristalsis • Nonabsorbable • Defecation usually occurs in 8–24 hours but may take up to 3 days to produce soft, well-formed stool

Bulk-forming examples

• Polycarbophil • Psyllium • Polyethylene glycol (PEG) • Methylcellulose • Polycarbophil contains high calcium content • Psyllium becomes viscous when mixed with water

Powdered bulk-forming laxatives

• Mix powder in a glass of water or juice • Stir • Consume immediately • Follow with half or full glass of water • May come flavored or sugar-free

Osmotic/saline laxatives

• Hyperosmolar products pull water into the colon • Increase water in feces and bulk • Stimulate peristalsis • Can produce semiformed to watery stools • Good renal function is required • Module lists heart failure as a contraindication

Osmotic/saline laxative examples

• Sodium salts = sodium phosphate, sodium diphosphate • Magnesium salts = magnesium hydroxide, magnesium citrate • High doses may be used for bowel preparation before diagnostic/surgical procedures

Polyethylene glycol with electrolytes

• Isotonic, nonabsorbable substance • About 3–4 L may be needed for bowel preparation • Store in refrigerator

Lactulose

• Nonabsorbable osmotic laxative • Contains glucose and fructose • Decreases serum ammonia level

Peptic ulcer

• Erosion occurring in the esophagus, stomach, or duodenum

Non-pharmacologic measures for peptic ulcer

• Avoid tobacco and alcohol • Encourage weight loss • Avoid hot, spicy, and greasy foods • Avoid caffeinated beverages • Offer dry crackers as needed

Antiulcer drugs

• Used to prevent or treat peptic ulcers

Tranquilizers for peptic ulcer

• Reduce vagal nerve stimulation and anxiety • Have minimal effect in preventing/treating ulcers • Examples = chlordiazepoxide and clidinium bromide • Adverse effects = edema, ataxia, confusion, agranulocytosis

Anticholinergics for peptic ulcer

• Inhibit acetylcholine and block histamine/hydrochloric acid • Decrease GI motility and secretion to relieve pain • Used for duodenal ulcers • Module identifies as first drug of choice for peptic ulcer • Examples = propantheline bromide, glycopyrrolate

Anticholinergic administration

• Take 30 minutes–1 hour BEFORE meals and at least 2 hours AFTER evening meal • Give antacid 2 hours after anticholinergic • Used as adjunctive therapy • Side effects = dry mouth, decreased secretions, headache, blurred vision, drowsiness, dizziness

Antacids

• Neutralize HCl and reduce pepsin activity • Classified as systemic or non-systemic

Sodium bicarbonate

• Systemic antacid • Seldom used for peptic ulcer • Can cause hypernatremia, water retention, metabolic alkalosis, and acid rebound

Calcium carbonate

• Systemic antacid • Has strong neutralizing power • About 1/3–1/2 is systemically absorbed • Can cause hypercalcemia and milk-alkali/Burnett syndrome

Aluminum hydroxide

• Non-systemic antacid • Can cause constipation • Used to lower high serum phosphate

Magnesium hydroxide

• Non-systemic antacid • Can cause diarrhea • Contraindicated in impaired renal function

Aluminum hydroxide + magnesium hydroxide

• Combination antacid used to reduce side effects of either drug alone • Give 1–3 hours after meals and at bedtime • Chewable tablet = follow with water • Liquid = take with water

Histamine-2 blockers

• Block H2 receptors on gastric parietal cells • Reduce gastric acid secretion and concentration • Used for gastric and duodenal ulcers • Administer before meals and at bedtime • Examples = famotidine, nizatidine, cimetidine

Famotidine

• H2 blocker • Used for Zollinger-Ellison syndrome • Good kidney function is required according to module • Used to prevent recurrence of duodenal ulcer at 40 mg once daily at bedtime

Nizatidine

• H2 blocker • Used for nocturnal gastric acid secretion • Used to prevent recurrence of duodenal ulcer at 150 mg BID

Cimetidine

• H2 blocker • Module notes shorter duration and more drug interactions than other listed H2 blockers

Proton pump inhibitors (PPIs)

• Also called gastric acid secretion/pump inhibitors • Suppress gastric acid by blocking the final stage of acid production • Administer before meals and at bedtime • Examples = omeprazole, lansoprazole, rabeprazole, esomeprazole, pantoprazole, dexlansoprazole

Omeprazole

• First PPI marketed • Takes days to produce an effect

Lansoprazole

• PPI • Ulcer relief usually occurs within about 1 week

Rabeprazole

• PPI • More effective for duodenal than gastric ulcers according to module • Effective for GERD and hypersecretory disease

Esomeprazole

• PPI • Module identifies highest success rate for healing erosive GERD

Pantoprazole

• PPI • Used for short-term erosive GERD • IV preparation can be effective for Zollinger-Ellison syndrome

Dexlansoprazole

• PPI • Used for erosive esophagitis and symptomatic non-erosive GERD

Pepsin inhibitors/mucosal protective drugs

• Cover the ulcer and protect it from pepsin • Administer before meals and at bedtime

Sucralfate

• Mucosal protective/pepsin inhibitor • Dosage = 1 g QID • If given with antacids, administer antacid 30 minutes before or after sucralfate • Side effects = headache, dizziness, constipation

Prostaglandin analogue

• Suppresses gastric acid secretion • Increases cytoprotective mucus in GI tract • Administer before meals and at bedtime

Misoprostol

• Prostaglandin analogue • Used for patients with gastric distress from long-term NSAID therapy • CONTRAINDICATED in pregnant women