Week 2 Pharmacology

drugs for PUD: H2 receptor antagonist, proton pump inhibitors, antacids, antibiotics

histamine-2 receptor antagonist: Ranitidine

Ranitidine: blocks H2 receptors in the parietal of the stomach, reducing the volume of gastric juice and decreases concentration of acid

ranitidine indications: PUD, GERD

ranitidine nursing considerations: increase risk pneumonia, assess signs of confusion, assess epigastric/abdominal pain, assess signs of GI bleeding

proton pump inhibitors: Omeprazole

omeprazole: causes irreversible inhibition of H+, K+ATPase, the enzyme that generates gastric acid - drug is acid-labile so capsules contain enteric coated granules

omeprazole adverse effects: headache, diarrhea, nausea, vomiting, pneumonia, fractures, dyspepsia, hypermagnesium

omeprazole nursing considerations: administer before meals, monitor serum magnesium, monitor for signs of pneumonia, monitor for fractures

other antiulcer drugs: sucralfate, misoprostol, antacids

sucralfate: undergoes chemical reaction in acidic environment of stomach to form a sticky gel - protects against ulcers by creating a mucosal barrier against acid and pepsin

sucralfate indications: GERD, duodenal ulcers

sucralfate adverse effects: constipation (rare), no systemic side effects because not absorbed

sucralfate nursing considerations: PO only, don’t take within 30mins of antacids, take 2hrs apart from other medications

misoprostol: replaces endogenous prostaglandin = suppress gastric acid secretion, promote bicarb/mucous secretion, increase mucosal blood flow

misoprostol indication: prevented NSAID induced gastroduodenal ulcers

misoprostol adverse effects: minimal, diarrhea

misoprostol nursing considerations: contraindicated in pregnancy - will cause spontaneous abortion

antacids: alkaline compounds that neutralize stomach acids = raise stomach pH above 5, reduce pepsin activity, stimulate prostaglandin production

antacids indications: GERD, PUD, gastritis

antacids: magnesium hydroxide (milk of magnesia), aluminum hydroxide (Almajel), calcium carbonate (TUMS), sodium bicarbonate

magnesium hydroxide adverse effects: diarrhea (often administered with aluminum hydroxide to counteract), avoid in patients with undiagnosed abdominal pain, magnesium can accumulate in patients with renal dysfunction

aluminum hydroxide (Almajel) adverse effects: constipation, high affinity for phosphate (=hyperphosphatemia)

calcium carbonate (TUMS) adverse effects: constipation, belching, flatulence, risk for acid rebound, calcium can accumulate in kidney failure

sodium bicarbonate adverse effects: belching, flatulence, in renal failure can cause systemic alkalosis, high risk of sodium loading (dangerous for HTN, HF)

antacids nursing considerations: monitor GI function, monitor electrolytes, give after meals

antibacterial drugs for PUD: amoxicillin, metronidazole, clarithromycin, tetracycline

laxatives: bulk forming, surfactant, stimulant, osmotic

bulk forming laxatives: Psyllium

psyllium indications: chronic constipation, prevent straining of stool, IBS

psyllium: made of polysaccharides and cellulose derived from grains and plant - increase bulk = soft formed stool

psyllium classification: Lehne Classification III - stool in 1-3 days

osmotic laxatives: lactulose, laxative salts (magnesium hydroxide, polyethelene glycol)

lactulose: made of galactose + fructose - turns into lactic acid in colon which has similar osmotic action to others

lactulose classification: Lehne Group III - 1-3 days

laxative salts (magnesium hydroxide): poorly absorbed salts and osmotic action draw water into intestinal lumen

laxative salts contraindications: patients with kidney disease

laxative salts (magnesium hydroxide) nursing considerations: low dose therapy stool in 6-12 hours; high dose for bowel evacuation prior to surgery or to purge poison

laxative salts (magnesium hydroxide) classification: Lehne category 1

polyethelene glycol: non absorbable compound that retains water in intestinal lumen - causes feces to swell and soften

polyethelene glycol adverse effects: GI side effects - nausea, bloating, cramping, flatulence, diarrhea

polyethelene glycol classification: Lehne category II-III depending on dose

stimulant laxatives: bisacodyl

bisacodyl (Dulcolax): stimulate intestinal motility and increase amount of water and electrolytes within bowel

bisacodyl nursing considerations: for opioid induced constipation, common drug for laxative abuse, via rectal suppository or mouth, give at bedtime

bisacodyl classification: Lehne group II - when given orally 6-12 hr stool

surfactant laxatives: docusate sodium (Colace)

docusate sodium (Colace): work in small intestine and colon to soften stool by facilitating penetration of water; also causes secretion of water and electrolytes into intestine (slow onset)

docusate sodium adverse effects: mild cramping, diarrhea

ducosate sodium classification: Lehne group III - stool 1-3 days

nonspecific anti-diarrheals: opioids (loperamide, dyphenoxelate atropine), bismuth subsalicylate

opioids: activate opioid receptors in GI to slow intestinal motility = more time for absorption of fluid and electrolytes - most effective anti-diarrheal

diphenoxylate + atropine (Lomotil): opioid for diarrhea, atropine to discouarge abuse - PO route only

diphenoxylate + atropine (Lomotil) adverse effects: dizziness, drowsiness, light headedness, headache, nausea, vomiting

loperamide (Imodium): suppresses bowel motility and bowel secretions; reduces volume of discharge from ileostomies

bismuth subsalicylate (Pepto Bismol): coats walls of GI tract - binds to causative bacteria or toxic which is then eliminated in stool

bismuth subsalicylate (Pepto Bismol) adverse effects: increased bleeding time, constipation, dark stools, hearing loss, tinnitus, metallic taste, bleeding gums

antiemetics: serotonin receptor antagonist, glucocorticoids, dopamine antagonists, cannabinoids, antihistamines/anticholinergics

serotonin receptor antagonists: Ondansetron

ondansetron (Zofran): works in chemoreceptor trigger zone - acts on serotonin, blocking receptors = less available serotonin

ondansetron (Zofran) indications: nausea associated with chemotherapy, radiation, anesthesia, viral gastritis, pregnancy

ondansetron (Zofran) nursing considerations: PO, IV, IM, often used with dexamethasone to increase effectiveness, monitor EKG in at risk patients, monitor effectiveness

ondansetron (Zofran) adverse effects: headache, constipation, diarrhea, dizziness, urinary retention, muscle pain, QT prolongation

glucocorticoid: dexamethasone

dexamethasone: unknown mechanism

dexamethasone indications: nausea associated with chemotherapy

dexamethasone nursing considerations: PO, IV

dopamine antagonist: metoclopramide (Maxeran)

metoclopramide (Maxeran): prokinetic drug - blocks dopamine and serotonin receptors in chemoreceptor trigger zone, enhances upper GI tract response to acetylcholine = increase peristalsis

metoclopramide (Maxeran) indications: nausea caused by post op, cancer medications, opioids, toxins, radiation

metoclopramide (Maxeran) adverse effects: diarrhea, sedation (high doses), risk of tardive dyskinesia with long term use (repetitive involuntary movements of arms, legs, facial muscles)

metoclopramide (Maxeran) contraindications: patients with GI obstruction, perforation or hemorrhage

metoclopramide (Maxeran) nursing considerations: GI assessment, assess mental status, look for uncontrolled movement

cannabinoids: Nabilone

nabilone: mechanism likely activation of receptors around vomiting center

nabilone indications: suppress chemotherapy induced nausea and vomiting

nabilone nursing considerations: monitor for drowsiness

nabilone side effects: CNS - temporal disintegration, dissociation (avoid wth psychiatric disorders); CVS - tachycardia, hypotension (avoid with CVD)

antihistamine: dimenhydrinate (Gravol)

dimenhydrinate (Gravol): blocks H1 receptors in GI tract and muscarinic receptors in vestibular system

dimenhydrinate (Gravol) indications: motion sickness, radiation sickness, post op nausea, drug-induced nausea

dimenhydrinate (Gravol) adverse effects: drowsiness, hypotension, dry mouth, constipation

dimenhydrinate (Gravol) nursing considerations: avoid w other CNS depressants, GI assessment, assess alertness, vital signs, monitor for signs of retention

muscarinic antagonist: Scopolamine

scopolamine: blocks nerve impulses between vestibular apparatus in inner eat and vomiting center

scopolamine indications: motion sickness (most effective)

scopolamine nursing considerations: PO, SC, transdermal dosing, GI assessment, monitor for signs of retention, assess alertness

scopolamine adverse effects: dry mouth, blurred vision, drowsiness, urinary retention, constipation, disorientation

drugs for IBD: 5-aminosalicylates, glucocorticoids, immunosuppressants, immunodulator

5-aminosalicylates: Sulfasalazine

sulfasalazine: action on prostaglandin synthesis and suppression of migration of inflammatory cells into affected region

sulfasalazine indications: mild to moderate IBD, maintain remission (after symptoms improved)

sulfasalazine nursing considerations: monitor CBC (can cause hematological disorders)

sulfasalazine adverse effects: nausea, fever, rash arthralgia

glucocorticoids: budesonide

budesonide: induce remission (not for long term maintenance); anti inflammatory action

budesonide nursing considerations: IV, PO (enteric coated capsule), prolonged use can cause severe adverse effects, adrenal suppression, osteoporosis, increase risk infection, Cushing’s syndrome

budesonide indications: mild to moderate UC (works locally within ileum and ascending colon)

immunosuppressant: Cyclosporine

Cyclosporine: calcineurin inhibitor (strong immunosuppressant) - long term therapy

cyclosporine indications: severe disease that has not responded to other therapies, both UC and Chron’s

cyclosporine nursing considerations: potentially toxic compound (= renal impairment, neurotoxicity), general suppression of immune system (= increase risk infection)

immunomodulator: Infliximab

infliximab: monoclonal antibodies designed to neutralize TNF (key immunoinflammatory modulator)

infliximab indications: moderate to severe UC and Crohn’s

infliximab nursing considerations: infections common, increase risk lymphoma, 6 week regimen followed by maintenance infusions every 8 weeks after

infliximab infusion reactions: fever, chills, pruritus, urticaria, cardiopulmonary reactions (chest pain, HTN, hypotension)