First Confirmed Case of Tegoprazan-Induced Anaphylaxis Demonstrated by Drug Provocation Testing

Tegoprazan, a potassium-competitive acid blocker, is commonly prescribed for the treatment of acid-related gastrointestinal diseases. Aside from a single reported case of tegoprazan-induced urticaria, no serious hypersensitivity reactions have been documented. Herein, we present a case of tegoprazan-induced anaphylaxis that evolved from an earlier and less severe reaction. The first episode manifested as manageable urticarial eruptions and resolved after discontinuation of the medication, whereas re-exposure provoked immediate anaphylaxis, with the initial cutaneous reaction escalating to systemic involvement with hypotension. A 42-year-old woman with nonerosive reflux disease presented to the emergency room (ER) with the sudden onset of a generalized rash after taking medications, including tegoprazan, for 8 days. After medical treatment and drug discontinuation, the patient’s symptoms improved without recurrence. However, 9 days later, immediately after readministration of the same drugs, she experienced severe shortness of breath, dizziness, facial swelling, generalized rash, itching, temporary loss of consciousness, and hypotension. The patient was transferred to the ER, where anaphylaxis was diagnosed. Following the administration of a single dose of intramuscular epinephrine, her systemic symptoms improved. Drug provocation tests (DPTs), together with a high Naranjo score, strongly supported tegoprazan as the culprit drug at the patient level. To our knowledge, this is the first reported case of tegoprazan-induced anaphylaxis confirmed by a formal diagnostic workup that included DPTs. Physicians should be aware of the potential for severe hypersensitivity reactions to tegoprazan.