Proton Pump Inhibitors

Abstract

Proton pump inhibitors (PPIs), omeprazole, lansoprazole, pantoprazole, rabeprazole, esomeprazole, and dexlansoprazole bind irreversibly to the H⁺, K⁺- ATPase (the “proton pump”) inhibiting its activity and decreasing gastric acid production. Systemic reactions to PPIs include anaphylaxis, urticaria, angioedema, interstitial nephritis, and thrombocytopenia. Cutaneous reactions include contact dermatitis, maculopapular and lichenoid eruptions, vasculitis, exfoliative erythrodermia, AGEP, DRESS, and SJS/TEN. Autoimmune reactions, including cutaneous lupus erythematosus, have been described. Cross-reactions between PPIs may be limited to one or two drugs or all drugs may be recognized. Cross-reaction studies so far have been based on skin testing, but the interpretations lack a quantitative basis. Successful oral desensitization following anaphylaxis to a PPI has been achieved in a few hours. Skin testing and challenge testing have been the only procedures employed to diagnose immediate reactions to PPIs. A suitable test for the detection of PPI-specific IgE antibodies is not yet available, and application of the positive basophil activation test has been limited.