For Helicobacter pylori eradication in a penicillin-allergic patient, which regimen is appropriate?

• A. Metronidazole, Clarithromycin and Lansoprazole for 7 days
• B. Amoxicillin-based triple therapy
• C. Levofloxacin-based therapy
• D. Doxycycline-based therapy

Answer: (A)

When treating Helicobacter pylori in someone who cannot take penicillin, you avoid regimens that include amoxicillin and instead use a triple therapy that substitutes a non-penicillin antibiotic. The idea is to pair a proton pump inhibitor (PPI) with two antibiotics that work by different mechanisms, improving the chance of eradication and compensating for the allergy.

The chosen regimen uses a PPI (to reduce gastric acidity and boost antibiotic effectiveness) plus clarithromycin and metronidazole. This combination directly addresses the allergy by removing amoxicillin from the plan and substituting metronidazole, while still providing a two-antibiotic approach to minimize resistance impact. Seven days is a common duration for this approach, balancing simplicity and efficacy.

The other options aren’t appropriate first-line choices in penicillin allergy because they rely on amoxicillin or use regimens that aren’t standard for initial therapy in this setting. Levofloxacin- or doxycycline-based options may be used in salvage scenarios after failure of first-line therapy, but they aren’t the preferred initial regimen for penicillin-allergic patients.