Postictal anticonvulsant drugs levels in unselected patients with poorly controlled epilepsy

Anticonvulsant drug levels were determined in thirty-six adult epileptic patients consecutively admitted to the emergency room because of generalized tonic-clonic seizures. Blood samples were drawn within two hours from the seizure. The drugs tested were phenytoin (n=23), carbamazepine (n=16), valproate (n=9), phenobarbitone (n=8), and primidone (n=1). Out of 22 patients on monotherapy, fifteen had serum drug levels below the 'therapeutic' ranges. All the fourteen patients receiving more than one drug had at least one level beneath the 'therapeutic' range. Generalized tonic-clonic seizures in treated patients are suggestive of subtherapeutic levels,and call for reassessment of the therapy. Determination of blood levels is helpful in the management of uncontrolled epilepsy, and assessment of such levels as soon as possible affer a seizure is indicated.