Drug therapy for Helicobacter pylori infection: problems and pitfalls.

Antibacterial chemotherapy against Helicobacter pylori is currently being assessed by open or randomized controlled clinical studies for its efficacy in eradicating this bacterium from the stomach of patients with gastritis or gastroduodenal ulcer. Whereas there is presently no "optimal" agent and treatment scheme, the combination of some antibiotics (metronidazole, tinidazole, amoxicillin) with bismuth salts proves definitely superior in vivo to either of these agents administered alone. Several reasons have been proposed, to explain the clinical failure after treatment: insufficient concentration of active drugs in gastric mucus, instability of some agents at an acidic pH, inappropriate formulation of drug, insufficient duration of treatment, and variable compliance of patients. Recently, it has appeared from several clinical trials that H. pylori may rapidly acquire resistance to some antibiotics, and that this event might also account for clinical failure. A critical review of the literature on H. pylori treatment indicates that association of bismuth and antibiotics or of antibiotics alone both may efficiently reduce the risk of emergence of resistance and improve the therapeutic outcome. Guidelines of treatment are suggested in order to avoid the future misuse of antibiotics that would increase selection of antibiotic-resistant H. pylori and negatively affect the ecology of the gastric microflora. Likewise, an accurate definition of a subset of patients with H. pylori who really will require treatment needs to be rapidly established.