Suspected lamotrigine-induced toxic epidermal necrolysis

To describe a patient who developed toxic epidermal necrolysis (TEN) possibly secondary to lamotrigine use.

A 74-year-old white man with a history of probable complex partial seizures was admitted to the neurology service for a prolonged postictal state. His antiepileptic regimen was changed while he was in the hospital to include lamotrigine. After 19 days of hospitalization and 14 days of lamotrigine therapy, the patient became febrile. The next day he developed a rash which progressed within 4 days to TEN, diagnosed by skin biopsy. All suspected drugs were discontinued, including lamotrigine. The patient was treated with hydrotherapy in the burn unit. His symptoms improved and he was discharged from the hospital 26 days after the rash developed.

During lamotrigine's premarketing clinical trials, the manufacturer reported several cases of Stevens-Johnson syndrome and TEN. There are several published case reports of lamotrigine-induced severe skin reactions. All of these reports included patients being treated with both valproic acid and lamotrigine. Our patient was exposed to phenytoin, carbamazepine, clindamycin, and lamotrigine, but not valproic acid. The patient reported prior use of phenytoin with no skin rash. Carbamazepine was the antiepileptic drug the patient was maintained on prior to his hospital admission, and the symptoms of TEN resolved while he was still receiving carbamazepine. The patient received only two doses of clindamycin, which makes this agent an unlikely cause of TEN.

Because of the temporal relationship of the onset of the patient's rash and several drugs that are known to cause severe rashes, it is not certain which drug was the definite culprit. However, based on the evidence from the literature, lamotrigine appears to be the causative agent.