Antiepileptics, drug utilization, defined daily dose, TDM

Prescribed daily doses (PDDs) of antiepileptic drugs (AED) (N03A ATC group) were recorded for drugs used in monotherapy or in combination therapy in the University Hospitals in Ostrava, Czech Republic and Huddinge, Sweden. Plasma concentrations were used as an indicator of the quality of treatment. The PDDs of most of the AEDs were lower than the DDDs. PDDs in monotherapy were only slightly lower than in combination therapy. Patients with plasma concentrations within the therapeutic range were usually treated with slightly higher doses than the remainder. In general, plasma concentrations tended to be in the low therapeutic range. The differences in PDDs between hospitals were significant in the case of valproic acid, phenobarbital (except monotherapy within), vigabatrin, and gabapentin, and carbamazepine. Our data suggest that the DDDs of AEDs should be reconsidered as, in the majority of cases, they appear to be too high.