Which of the following correctly matches an antiepileptic agent with its primary toxicity?
(A) carbamazepine—trigeminal neuralgia
(B) ethosuximide—gingival hyperplasia
© lamotrigine—life-threatening dermatitis
(E) valproic acid—sedation
© Lamotrigine causes a variety of minor adverse effects, but its most serious toxicity is a potentially life-threatening dermatitis. Carbamazepine (choice A) is effective in the treatmentof trigeminal neuralgia. Its major toxicities involve diplopia and ataxia in overdose. Ethosuximide (choice B) causes sedation as its primary toxicity. Vigabatrin causes visual field defects that may be irreversible. Phenytoin (choice D) causes diplopia, ataxia, and gingival hyperplasia. It has been associated with fetal abnormalities when taken by pregnant women. Valproic acid (choice E) rarely causes sedation. It is associated with a low but significant incidence of hepatic impairment. The cause is unknown, but the incidence is highest in patients less than 2 years of age and in those taking multiple medications, fatalities have resulted.