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Pharmacology Made Easy 4.0 Gastrointestinal System Questions and Answers | Latest Version | 2025/2026 | Correct & Verified
What is the primary mechanism of action of proton pump inhibitors?✔✔ Proton pump inhibitors irreversibly block the H+/K+ ATPase enzyme in gastric parietal cells, reducing acid production.
Why are antacids typically administered after meals?✔✔ Antacids work best when taken after meals because food slows gastric emptying, allowing longer contact time with stomach acid.
How does sucralfate protect ulcerated gastrointestinal tissue?✔✔ Sucralfate forms a viscous adhesive barrier that binds to ulcer sites, protecting them from acid and pepsin.
What makes misoprostol useful for preventing NSAID-induced gastric ulcers?✔✔ Misoprostol is a prostaglandin analog that enhances mucosal defense mechanisms and reduces acid secretion. 1 / 2
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Why must tetracycline antibiotics be spaced apart from antacids?✔✔ Antacids containing aluminum, calcium, or magnesium can chelate tetracyclines, significantly reducing their absorption.
What is the key difference between loperamide and diphenoxylate in treating diarrhea?✔✔ Loperamide acts solely on peripheral opioid receptors in the gut, while diphenoxylate has central nervous system effects at higher doses.
How does ondansetron prevent chemotherapy-induced nausea?✔✔ Ondansetron selectively blocks 5-HT3 serotonin receptors in the gut and chemoreceptor trigger zone, inhibiting nausea signals.
Why is vitamin B12 supplementation necessary with long-term PPI use?✔✔ Proton pump inhibitors reduce gastric acid needed to release vitamin B12 from food proteins, potentially causing deficiency.
What makes lubiprostone different from other laxatives?
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