Phenobarbital vs. phenytoin for grand mal epilepsy.

The chief side effect of phenobarbital is drowsiness, which is usually associated with overdosage. Phenytoin, on the other hand, causes gingival hyperplasia in many patients, irreversible hypertrichosis in some patients and lethal reactions, such as Stevens-Johnson syndrome, in a few patients. Antiepileptic therapy should always be started with one drug.