Pharm 2 Final: GI Drugs

Famotidine (Pepcid)

MOA: H2 receptor antagonist. Use: Dyspepsia, peptic ulcer disease, GERD. SE: For PUD, give single daily dose at bedtime.

Omeprazole (Prilosec)

MOA: Proton pump inhibitor; inhibits H+/K+-ATPase in gastric parietal cells. Use: Dyspepsia, PUD, GERD. SE: Low magnesium; high-dose PPI linked to chronic kidney disease and increased osteoporosis risk.

Calcium Carbonate

MOA: Gastric antacid. Use: Dyspepsia/GERD. SE: Constipation; rebound acid secretion with large doses.

Hydrocortisone

MOA: Glucocorticoid. Use: Ulcerative colitis, Crohn's disease. SE: Can be given as rectal enema; common steroid side effects.

Mesalamine

MOA: Metabolite of sulfasalazine; inhibits prostaglandin synthesis (anti-inflammatory). Use: Ulcerative colitis, Crohn's disease. SE: N/A.

Metoclopramide (Reglan)

MOA: Prokinetic; blocks dopamine D2 receptors to increase GI motility; also blocks D2 and 5-HT3 in chemoreceptor trigger zone (antiemetic). Use: GERD, diabetic gastroparesis, intractable hiccups. SE: Antiemetic effect.

Polyethylene Glycol (Miralax)

MOA: Osmotic laxative; retains water in intestinal lumen, increases intraluminal pressure, stimulates peristalsis. Use: Constipation. SE: Electrolyte abnormalities; avoid sodium phosphate in renal impairment.

Psyllium (Metamucil)

MOA: Bulk-forming laxative; absorbs and retains water in intestinal lumen. Use: Constipation. SE: Rarely causes adverse effects.

Docusate (Colace)

MOA: Surfactant laxative (stool softener). Use: Constipation. SE: Softens stool but minimal evidence of increased gut motility.

Linaclotide (Linzess)

MOA: Increases secretion of chloride and bicarbonate into intestines, increasing intestinal fluid and motility. Use: Chronic idiopathic constipation (CIC), IBS-C. SE: Diarrhea (most common).

Senna (Senokot)

MOA: Stimulant laxative; acts directly on intestinal mucosa to stimulate peristalsis. Use: Constipation. SE: Abdominal pain and cramping.

Loperamide (Imodium)

MOA: Opioid agonist in GI smooth muscle. Use: Diarrhea. SE: N/A.

Ondansetron (Zofran)

MOA: 5-HT3 antagonist. Use: Nausea and vomiting. SE: Higher doses associated with QTc prolongation.

Dronabinol (Marinol)

MOA: Oral THC formulation. Use: Chemotherapy-induced emesis; appetite stimulant. SE: N/A.