A 40-year-old man has a positive urea breath test for H. pylori and a duodenal ulcer on upper GI endoscopy. He is allergic to penicillin. Which H. pylori eradication regimen is appropriate?
- A Bismuth quadruple therapy: PPI + bismuth + metronidazole + tetracycline for 14 days ✓
- B Standard triple therapy: amoxicillin + clarithromycin + PPI for 14 days
- C Dual therapy: PPI + clarithromycin for 7 days
- D Sequential therapy: amoxicillin + PPI for 5 days then clarithromycin + metronidazole + PPI for 5 days
Correct answer: A. Bismuth quadruple therapy: PPI + bismuth + metronidazole + tetracycline for 14 days
Explanation
In penicillin-allergic patients, amoxicillin-containing regimens (standard triple therapy and sequential therapy) are contraindicated. Bismuth quadruple therapy (PPI + bismuth subcitrate + metronidazole + tetracycline for 10–14 days) is the preferred first-line alternative, achieving eradication rates >90%. The ACG and AGA 2022 guidelines also recommend vonoprazan-based regimens where available. Levofloxacin-based triple therapy is another option but fluoroquinolone resistance is increasing globally. Dual PPI + clarithromycin is insufficient as monotherapy.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
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Written and medically reviewed by the StethoPrep medical team.