How does Helicobacter pylori infection interact with non-steroidal anti-inflammatory drugs?

There have been conflicting clinical data on whether Helicobacter pylori (H. pylori) contributes to the pathogenesis of ulcers induced by non-steroidal anti-inflammatory drugs (NSAIDs). The discrepant findings reflect the complex interaction between H. pylori and NSAIDs, which has generated divergent results under different clinical conditions. This chapter reviews the pathogenetic mechanisms in ulcer formation that are common to H. pylori and NSAIDs, and explains how a better understanding of these factors might resolve some of the controversies. Existing evidence indicates that the interaction between H. pylori and NSAIDs is not an 'all-or-none' relationship. Factors such as previous exposure to NSAIDs, a past history of ulcer complication, gastric acid output, neutrophil infiltration, concurrent acid suppressive therapy and the type of NSAID used (aspirin versus non-aspirin NSAIDs) would influence the role of H. pylori as a risk factor in NSAID users. Recommendations on H. pylori eradication for different subgroups of NSAID users are proposed.