Week 15 Flash Cards

Question 1

PPI Mechanism of Action

Answer 1

Irreversibly inhibits the H+/K+-ATPase enzyme (proton pump) in gastric parietal cells to block the final step of acid secretion.

Question 2

PPI Duration of Action

Answer 2

Lasts ~24 hours despite a short half-life due to irreversible binding to the proton pump.

Question 3

PPI Administration Timing

Answer 3

Best taken 30–60 minutes before meals to coincide with active proton pumps.

Question 4

PPI Clinical Uses

Answer 4

First-line treatment for GERD, peptic ulcers, H. pylori eradication regimens, Zollinger-Ellison syndrome, and NSAID-induced ulcers.

Question 5

PPI Adverse Effects

Answer 5

Long-term use may cause hypomagnesemia, vitamin B12 deficiency, fractures, pneumonia, and C. difficile infection.

Question 6

PPI Metabolism

Answer 6

Metabolized by liver enzymes CYP2C19 and CYP3A4, which can cause drug interactions.

Question 7

H2 Blocker Mechanism of Action

Answer 7

Reversibly blocks histamine at H2 receptors on gastric parietal cells, reducing acid secretion.

Question 8

H2 Blocker Uses

Answer 8

Used for GERD, peptic ulcers, and stress ulcer prophylaxis, particularly in ICU patients.

Question 9

H2 Blocker Renal Considerations

Answer 9

Dose adjustment required in patients with renal impairment due to renal excretion.

Question 10

Cimetidine Side Effects

Answer 10

May cause gynecomastia, galactorrhea, CNS effects in elderly, and CYP450 drug interactions.

Question 11

Antacid Mechanism of Action

Answer 11

Neutralizes existing gastric acid to provide rapid symptom relief.

Question 12

Magnesium Antacid Side Effect

Answer 12

Diarrhea is a common side effect.

Question 13

Aluminum Antacid Side Effect

Answer 13

May cause constipation.

Question 14

Calcium Carbonate Antacid Side Effect

Answer 14

Can cause rebound acid secretion and gas.

Question 15

Antacid Use Consideration

Answer 15

Provides short-term relief but does not heal ulcers or eradicate H. pylori.

Question 16

Misoprostol Mechanism of Action

Answer 16

Prostaglandin E1 analog that reduces acid and increases mucus and bicarbonate secretion.

Question 17

Misoprostol Use

Answer 17

Used to prevent NSAID-induced ulcers in high-risk patients.

Question 18

Misoprostol Contraindication

Answer 18

Contraindicated in pregnancy due to risk of uterine contractions.

Question 19

Sucralfate Mechanism

Answer 19

Binds to ulcer base, forming a protective barrier without altering gastric pH.

Question 20

Sucralfate Use

Answer 20

Used as a mucosal protectant in peptic ulcer disease, often adjunctively.

Question 21

5-HT3 Antagonists Mechanism

Answer 21

Blocks serotonin receptors in the GI tract and brain; used for chemo and post-op nausea.

Question 22

5-HT3 Antagonists Examples

Answer 22

Ondansetron and granisetron.

Question 23

Dopamine Antagonist Use

Answer 23

Used as antiemetics (e.g., promethazine, prochlorperazine) but may cause sedation and EPS.

Question 24

Metoclopramide Mechanism

Answer 24

Dopamine antagonist with prokinetic and antiemetic properties; increases GI motility.

Question 25

Metoclopramide Use

Answer 25

Used in gastroparesis and nausea associated with migraines or chemotherapy.

Question 26

Metoclopramide Adverse Effects

Answer 26

May cause sedation, dystonia, and Parkinson-like symptoms.

Question 27

Benzodiazepine Use in GI

Answer 27

Used for anticipatory nausea in chemotherapy; provides anxiolysis and sedation.

Question 28

Antidiarrheal Mechanism

Answer 28

Slows intestinal motility by acting on opioid receptors in the gut.

Question 29

Loperamide Use

Answer 29

Over-the-counter antimotility agent used for symptomatic diarrhea relief.

Question 30

Diphenoxylate-Atropine Risks

Answer 30

Risk of CNS effects and anticholinergic toxicity, especially in high doses.

Question 31

Antidiarrheal Contraindication

Answer 31

Avoid in cases of bloody or infectious diarrhea.

Question 32

Absorbent Mechanism

Answer 32

Binds toxins, bacteria, and fluids in the GI tract; less potent than antimotility agents.

Question 33

Bulk Laxative Mechanism

Answer 33

Non-digestible fibers increase stool bulk and stimulate motility (e.g., psyllium).

Question 34

Osmotic Laxative Mechanism

Answer 34

Draws water into the bowel to soften stool and promote evacuation (e.g., PEG, lactulose).

Question 35

Stimulant Laxative Mechanism

Answer 35

Irritates the intestinal lining to promote peristalsis (e.g., senna, bisacodyl).

Question 36

Stool Softener Use

Answer 36

Preventive option to ease stool passage by mixing water and fat (e.g., docusate sodium).