Hesi Gastrointestinal System

Flashcards covering key GI pharmacology topics from the provided notes.

What reflex stimulates the stomach to prepare for food?

Gastroenteric reflex.

Which reflex increases colon activity when the stomach is stimulated?

Gastrocolic reflex.

Which reflex in the duodenum stimulates colon activity and mass movement?

Duodenal-colic reflex.

What is the mature vomiting center in the medulla called?

Chemoreceptor trigger zone (CTZ).

Name four histamine-2 receptor antagonists.

Ranitidine, famotidine, cimetidine, nizatidine.

How do H2 antagonists reduce acid production?

By blocking H2 receptors and suppressing gastrin release from parietal cells.

Where else are H2 receptors found besides the stomach, and what risk does this pose?

In the heart; potential for arrhythmias.

List common uses of H2 antagonists.

Short-term treatment of active duodenal/gastric ulcers; hypersecretion; stress-ulcer prophylaxis; GERD; relief of heartburn.

Which H2 antagonist is preferred in liver dysfunction?

Nizatidine.

Which H2-receptor antagonist was recalled due to NDMA?

Ranitidine.

What does NDMA stand for and why is it a concern?

N-nitrosodimethylamine; a probable human carcinogen linked to cancer risk.

Which H2 antagonist recall was voluntary?

Nizatidine.

List common adverse effects of H2 antagonists.

GI upset; dizziness; headache; confusion; arrhythmias; hypotension; gynecomastia; impotence.

What are the main active ingredients in common antacids?

Calcium carbonate, sodium bicarbonate, magnesium salts, aluminum salts.

What is the primary action of antacids?

To neutralize stomach acid.

Which antacid can cause constipation and acid rebound?

Calcium carbonate.

Which antacid commonly causes diarrhea and can act as a laxative?

Magnesium salts (e.g., Milk of Mag).

Which antacid does not cause acid rebound?

Aluminum salts.

What risk is associated with sodium bicarbonate as an antacid?

Electrolyte imbalances.

How should antacids be spaced with other medications?

Take other meds at least 2 hours before or after antacids to avoid interference with absorption.

What do proton pump inhibitors do?

Inhibit the H+/K+ ATPase (proton pump) in parietal cells to reduce acid secretion.

Name the proton pump inhibitors listed.

Omeprazole, esomeprazole, lansoprazole, pantoprazole.

What are common uses of PPIs?

Duodenal ulcers, GERD, erosive esophagitis, benign gastric ulcers, and H. pylori treatment with antibiotics.

Which PPI is approved for children under 18?

Lansoprazole.

What long-term risk is associated with PPIs?

Altered gastric flora with potential increased cancer risk due to reduced acidity.

How should PPIs be administered and for how long are they typically used?

Taken before meals; should not be crushed or chewed; usually 2–4 weeks, but can be longer with NSAID use.

What is sucralfate and its protective action?

Sucralfate coats ulcers to protect them from acid and bile, facilitating healing.

Who should avoid sucralfate?

Renal failure or dialysis patients due to aluminum buildup.

What pregnancy-related precautions apply to misoprostol?

A negative pregnancy test is required; start on day 2 or 3 of the cycle; use barrier contraception during treatment.

What is the primary use of misoprostol (Cytotec)?

To prevent NSAID-induced gastric ulcers by protecting the gastric mucosa.

What is pancrelipase used for?

Replacing pancreatic enzymes to aid digestion in pancreatic insufficiency or cystic fibrosis.

What are the three main classes of laxatives?

Chemical stimulants, bulk stimulants, and lubricants.

Name chemical stimulant laxatives listed and a key precaution with their use.

Bisacodyl, castor oil, senna; avoid taking with other meds within 30 minutes to prevent absorption issues.

What do bulk stimulant laxatives do?

Increase fecal bulk by drawing water into the intestines to stretch the walls and trigger reflexes.

Name examples of bulk stimulant laxatives.

Polyethylene glycol (MiraLax), magnesium hydroxide (Milk of Mag), polycarbophil (FiberCon), psyllium (Metamucil), GoLYTELY (PEG-electrolyte), lactulose (Constilac).

What are the lubricants used as laxatives and their effect?

Docusate, glycerin, and mineral oil; soften stools and ease defecation.

What is a key caution with long-term use of laxatives?

Potential for dependency and electrolyte/fluid disturbances; monitor the patient.

What is metoclopramide (Reglan) used for?

To stimulate GI motility and secretions by enhancing parasympathetic activity; also used as an antiemetic.

How do antidiarrheals like Pepto-Bismol and Imodium work?

Pepto-Bismol acts on the GI lining to inhibit local reflexes; Imodium slows GI tract motility by acting on intestinal muscles.

What antibiotic is used for traveler’s diarrhea?

Rifaximin.

What are the key features of the IBS drug lubiprostone?

Chloride-channel activator increasing chloride-rich intestinal fluid and motility; used for IBS-C.

What is alosetron used for and what are its restrictions?

Serotonin 5-HT antagonist for IBS-D; restricted to women with a patient-physician agreement and Black Box warnings.

What are antiemetic drug classes listed in the notes?

Phenothiazines, nonphenothiazines, 5-HT receptor blockers, NK1 receptor antagonists, and miscellaneous.

Give an example of a phenothiazine antiemetic and one major adverse effect.

Prochlorperazine; adverse effects include pink/red-brown urine, photosensitivity, CNS effects.

What are examples of 5-HT receptor blockers?

Ondansetron (Zofran) and dolasetron (Anzemet).

What are NK1 receptor antagonists and their use?

Aprepitant and rolapitant; used with chemotherapy to prevent delayed N/V by blocking CNS receptors.

What are cannabinoid antiemetics and when are they used?

Dronabinol (Marinol) and nabilone; used for chemo-induced N/V in patients who failed other therapies.