In-hospital gastric protection with proton pump inhibitors: adverse effects beyond (over)utilization?

Background: Proton pump inhibitors (PPIs) have provided important benefits in the management of gastroesophageal reflux disease (GERD), peptic ulcer disease and in the prevention of non steroidal antiinflammatory drugs and aspirin-related ulcer complications. PPIs are also the most commonly used medications for stress ulcer prophylaxis, despite little evidence to support their use in non-intensive care unit.
Discussion: Considering the widespread use of PPIs, these agents' overall safety profile is unquestionable. However, there is growing evidence that PPIs use may be associated with an increased risk of enteric infections, pneumonia, hip fractures, vitamin B12 deficiency. Overall, until now, none of these adverse effects have discouraged the PPIs treatment. Recently attention has been placed on a more important potential adverse effect of PPIs, their interaction with clopidogrel to which they are associated for the prophylaxis of gastrointestinal bleeding. Preliminary results of laboratory tests suggest that omeprazole reduces clopidogrel's antiplatelet effect. The interaction seems to involve the competitive inhibition of the CYP2C19 isoenzyme. The effect appears to be clinically important, as some retrospective studies have shown an increase in adverse cardiovascular outcomes when PPIs and clopidogrel are used concomitantly. Some studies indicate that pantoprazole and esomeprazole are not associated with impaired response to clopidogrel. However, the available data for PPIs other than omeprazole do not allow definitive conclusions to be drawn about whether is a class effect.
Conclusions: Specifically designed and randomized clinical studies are needed to define the interaction between PPIs and clopidogrel. Moreover, alternative treatment strategies with histamine- 2 receptor antagonists that are not dependent on cytochrome p450 2C19 should be tested in future studies.