The value of phenytoin plasma levels in the treatment of epilepsy.

Abstract

Phenytoin plasma levels were measured in epileptics whose condition was poorly controlled, in epileptics suspected to have phenytoin toxicity and in a group of neurosurgical patients who had had phenytoin prescribed for them and who were asymptomatic. In all groups many plasma levels were found below those regarded as therapeutically effective. The majority of patients were receiving additional anticonvulsant drugs. Measurements of plasma phenytoin levels are necessary for the efficient use of this drug in epilepsy.