Prophylactic phenytoin in severe head injuries.

We are reporting a retrospective study of 62 patients whose head injury was sufficiently severe to cause a high probability of posttraumatic epilepsy. Of 50 patients treated with phenytoin, 10% developed epilepsy of late onset. Twelve patients not treated with phenytoin but who had head injuries of equal magnitude had a 50% incidence of epilepsy. These data from a highly selected group of patients with severe head injuries confirm the bias that treatment with phenytoin decreases the incidence of posttraumatic epilepsy.