Severe allergic reactions associated to proton pump inhibitors

Published Online: January 21, 2016

Proton pump inhibitors (PPI) are a group of medications widely used to treat acid-related gastrointestinal disorders. In clinical practice they are frequently prescribed for gastric protection in combination with other drugs, such as non-steroidal anti-inflammatory drugs, antibiotics or corticosteroids, and some of them are available over the counter. PPI’s are considered remarkably safe and anaphylactic reactions are rarely reported, but PPI’s can cause hypersensitivity reactions
Mota et al. reported in The Journal of Allergy and Clinical Immunology: In Practice the occurrence of severe allergic reactions to PPI in five patients. The circumstances of drug intake, particularly in combination with other drugs more prone to induce allergic reactions and before meals, might delay the diagnosis. PPI are frequently forgotten as suspected culprits, which can led to subsequent repeated reactions.

The patients in this report developed symptoms within 30 to 60 minutes after oral intake, but a more rapid reaction occurred immediately after intravenous administration. Two patients had loss of consciousness. The patients underwent skin prick and intradermal testing with the suspected medication and similar compounds within same chemical group (omeprazole, esomeprazole and pantoprazole) to assess potential cross-reactivity. All patients showed positive skin tests to the suspected medication.  In two cases esomeprazole might be a safe alternative drug with negative skin tests, but most of the patients showed positive responses to all compounds tested.

Although widely prescribed and not usually suspected in cases of allergic reactions, this report aims to increase the awareness that PPI can be responsible for anaphylactic reactions. A delay in diagnosis or misdiagnosis might lead to repeated harmful exposure or unnecessary avoidance of drugs or foods until the correct diagnosis is made.      

The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.

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