Clinical relevance of the determination of antiepileptic drugs in serum.

Opinions on the clinical relevance of the determination of antiepileptic drugs in serum are very divergent. Specially the value of routine determinations has not been clarified up to now. At present the determination of antiepileptic drugs is indicated in the following situations: resistance to therapy including suspected irregular intake, adjustment of the serum level into the therapeutic range to prevent under- or overdosage, suspected intoxication (particularly during combined therapy), dosage monitoring when changes in the dosage-serum level relationship might occur, combined therapy, dosage reduction in the absence of seizures, determination of a baseline level in patients with good anticonvulsant control, legal indications, therapy research.