Pharmacology · patient case question
Omeprazole reduces gastric acid by acting on which target?
Patient case: Polypharmacy — Cardiovascular & GI
demo: 68-year-old male
chief: “I need a crown on my lower left molar.”
history: Hypertension, gastroesophageal reflux disease, atrial fibrillation, hyperlipidemia, gout. Non-smoker.
meds: Lisinopril, omeprazole, verapamil, apixaban, rosuvastatin, allopurinol
findings: BP 132/84 mmHg. Generalized attrition. Tooth #19 with fractured MOD amalgam, no pulpal symptoms. No active periodontal disease.
Show answer and explanation
Correct answer: D. The H⁺/K⁺-ATPase proton pump of gastric parietal cells
- A. That is the mechanism of ranitidine and famotidine, which are H₂ blockers, not PPIs.
- B. Gastrin receptor antagonism is not a clinically used mechanism for this drug class.
- C. Anticholinergics reduce acid through M3 blockade, but that is not omeprazole.
- D. Correct. Omeprazole is a proton pump inhibitor; it irreversibly binds the H⁺/K⁺-ATPase, the final common step of acid secretion.
Note: Dental relevance: PPIs raise gastric pH and therefore reduce absorption of azole antifungals (ketoconazole, itraconazole) and ampicillin, and they increase serum levels of benzodiazepines, phenytoin, and warfarin.