Severe cutaneous adverse reaction to drug excipient following brand-to-generic switch of levetiracetam.

Abstract

Levetiracetam is an antiepileptic drug known for its high tolerability, and severe adverse drug reactions are rare. We report the case of a severe cutaneous adverse drug reaction in a patient who was switched from brand-name to generic levetiracetam. A 29-year-old woman undergoing contrast-enhanced computed tomography developed lesions over her trunk starting 6 hours after imaging. Although initially diagnosed as an allergy to the radiocontrast agent, the condition progressively worsened into toxic epidermal necrolysis-drug reaction with eosinophilia and systemic symptoms overlap syndrome, despite adequate hydration and treatment. Investigation of the patient's medications revealed that she had been switched from brand-name to generic levetiracetam a week before the onset of symptoms. Levetiracetam was immediately discontinued, with the patient recovering after 2 weeks of intensive care. Adverse drug reaction analysis identified excipients in generic levetiracetam as the likely cause of the severe reaction. This is the first reported case of severe cutaneous drug allergy after a brand-to-generic switch for levetiracetam. Brand-to-generic switches of medications can potentially cause severe allergic reactions due to differences in excipients.