American College of Gastroenterology Clinical Guideline

Antibiotic Selection

There is increased resistance to clarithromycin, and traditional triple therapy (clarithromycin + amoxicillin + proton pump inhibitors [PPIs]) should not be prescribed unless the rates of clarithromycin resistance are known to be < 15%.

We should not use clarithromycin triple therapy.

Then what to use as First-Line Therapy

Quadruple therapy: Clarithromycin (500 mg), amoxicillin (1 g), metronidazole (500 mg), and a PPI, all given twice a day.

Or bismuth subsalicylate (2 tablets four times a day), metronidazole (500 mg three or four times a day), tetracycline (500 mg four times a day), and a PPI (twice a day). Patients on this regimen will need to be informed about bismuth-related stool darkening.

Or Triple therapy with levofloxacin (500 mg once a day), amoxicillin (1 g twice a day), and a PPI (twice a day) is an alternative but not recommended as the best initial option.

Treatment Duration

Recommendation is 14 days

Salvage Therapy for Persistent H pylori Infection

Avoid antibiotics previously used

Bismuth-based quadruple therapy or levofloxacin triple therapy are accepted salvage regimens.