[Ulcer drugs: profile of side effects of proton-pump blockers in comparison to H2 blockers in the spontaneous reporting system].

Inhibition of gastric acid secretion by drugs remains the most important rational approach to the treatment of acid related diseases. Histamine H2-antagonists and more recently the proton pump blockers have become the first line treatment for acid peptic diseases. Proton pump blockers bind specifically to the proton pump of the parietal cells and thus inhibit the final acid secretion independently from the activating stimuli. Because of this specific mechanism fewer adverse effects on other systems in the body are expected with proton pump blockers than with histamine antagonists. An analysis of the spontaneous reports which the Swiss Drug Monitoring Center (SANZ) received from 1981 to 1995 showed striking differences in the adverse drug reaction profile: hypersensitivity reactions with fever and anaphylactic reactions, liver disorders such as cholestatic hepatitis, most with severe progression and requiring hospitalization, as well as endocrine disorders were reported more frequently with histamine antagonists, skin reactions and joint disorders, however, were reported more often with proton pump blockers. Our data also support the conclusion that adverse drug reactions to proton pump blockers and histamine antagonists are rare in the spontaneous reporting scheme (reporting rate < 1%). There was a somewhat higher rate of serious reports with histamine antagonists. These data do not allow conclusions concerning long-term effects or effects with larger than recommended dosages.