Acute intermittent porphyria, seizures, and antiepileptic drugs: a report on a 3-year-old Nigerian boy.

A 3-year-old Nigerian boy was treated with phenobarbitone after having a nonfebrile seizure. Two weeks later his urine was found to contain porphobilinogen, indicating that latent acute intermittent porphyria had been unmasked by phenobarbitone. The drug was discontinued and carbamazepine was substituted. The urine became free of porphobilinogen and the patient remained well. In developing countries phenobarbitone is the most widely used anticonvulsant; it must be avoided in acute intermittent porphyria, and carbamazepine may be tolerated.