Anti-epileptic drug intake adherence. The value of the blood drug level measurement and the clinical approach.

It was evaluated the patient antiepileptic drug (AED) intake adherence in a pilot cross-sectional study carried out at a neurologic out-patient clinic of a university hospital. Ninety-three AED blood concentration (phenobarbital, phenytoin, carbamazepine) were analyzed from 24 patients. The variability of the AED blood level was measured (in the steady state period by means of the variation coefficient) and compared with the self-reported antiepileptic medication non-adherence, AED blood level according to the range (therapeutic or not), and the seizure control. It was not observed any strong correlation between the higher value of variability and the other three parameters of no adherence. The highest correlation was with the blood drug level (therapeutic or not). The evaluation of blood drug measurement alone, except in cases of extreme low adherence and variability of drug intake, is not enough for the recognition of incorrect drug intake, but the clinical markers and the self-reported adherence have to be also considered for this sort of evaluation.