Unusual side effects of lamotrigine therapy.

An 8-year-old boy developed tremor, unsteadiness, chorea, and eye movement abnormalities on starting lamotrigine for myoclonic jerks. Investigations for a neurodegenerative disorder were negative. Symptoms and signs resolved on stopping lamotrigine. He was well and asymptomatic on follow-up after 4 years. Another 7-year-old boy who started on lamotrigine for suspected absence seizures developed abnormalities of eye movement with associated cognitive decline, which also resolved on discontinuing the medication. Eye movement abnormalities, involuntary movements, and behavioral changes appear to be unusual side effects of lamotrigine therapy.