Amoxicillin for the treatment of Helicobacter pylori infection.

Amoxicillin is one of the most active antimicrobials against Helicobacter pylori in vitro, with a minimum inhibitory concentration (MIC) of < or = 0.01-0.1 mg/l. Thus far, neither primary nor secondary resistant strains have been found. Amoxicillin, which has a bactericidal effect on H. pylori, but is less inhibitory in the stationary growth phase and against cell-adherent or slowly growing H. pylori, probably has both topical and systemic activity. It is fairly acid stable and is less affected by gastric acidity than macrolides. Nevertheless, its activity in vivo is considerably enhanced when it is given concomitantly with proton pump inhibitors. Several amoxicillin-containing treatment regimes have yielded H. pylori eradication rates of > or = 90%. Of particular interest are 1-week treatment regimens containing amoxicillin + clarithromycin + omeprazole, or amoxicillin + metronidazole + omeprazole, as well as a 1-h topical therapy developed in Japan.