PPI adverse drugs reactions: a retrospective study

Proton pump inhibitors (PPIs) are drugs capable of blocking the gastric pump H,K-ATPase in order to inhibit gastric acid secretion. Omeprazole, lansoprazole, pantoprazole, rabeprazole and esomeprazole belong to PPIs category. Although PPIs have a good safety profile, allergic reactions to these molecules can occur. The real rate of hypersensitive reactions to PPIs is unknown. The aim of this retrospective study is to evaluate the rate of hypersensitive reactions to PPIs in patients admitted to our Unit between 2008 and 2013 with a history of drug hypersensitivity. From a database of 1229 patients (921 women, 308 men) with adverse drug reaction we extrapolated the data about PPI reactions. Twelve patients (10 female, 2 men) had a positive history for hypersensitive reaction to PPI. Pantoprazole was the most frequently PPI involved. Based on patient personal history in some cases we performed an oral challenge test for an alternative anti-acid drug and none of them had adverse reactions. According to our experience and according to the literature and pharmacovigilance reports, ADR caused by PPIs are ever increasing. Adverse reactions to these drugs are still under-reported; however, considering the frequency of their prescription worldwide, the risk of severe allergic events is low. Further studies are needed to provide clearer data on the real incidence and prevalence about this matter. This should be useful to help physician in choosing the molecule to prescribe and, in case of hypersensitivity, the alternative molecule to test, also considering the possible cross-reactivity.