Carbamazepine (Tegretol) as an anticonvulsant. A controlled double-blind comparison with diphenylhydantoin (Dilantin)

A large double blind crossover study of carbamazepine (CBZ) in comparison to diphenylhydantoin (DPH) is underway, and the results are presented for the first 20 patients to complete the protocol. The importance of preparatory steps is outlined-beginning with the gathering of preliminary kinetic data about half-life and peak-time in epileptic patients. A detailed pilot study was performed with open administration of the agents and hospitalization during the crossover. Detailed blood level monitoring and dose-equivalence calculations lead to the design of blind crossover protocol from the pilot study. Of the 20 patients reported on at this point, 12 had fewer seizures on CBZ, but 4 of these preferred DPH because of the CBZ side effects. Of the 8 having fewer seizures on DPH, 3 preferred CBZ - leading to a final disposition of 11 on CBZ and 9 on DPH. Mean serum levels were 34.1 mug/ml for DPH and 10.6 mug/ml for CBZ. The patients having fewer seizures on DPH had higher serum DPH levels than those doing better on CBZ, but the opposite was found for the CBZ levels. The implications of this difference are discussed. Over all, DPH and CBZ are effective anticonvulsants of the same general magnitude, but individual patient responses to effects and side-effects will influence their usefulness in any given case.