Antiepileptic drugs in epilepsy and other disorders—A population-based study of prescriptions

SummaryPurposeThe aim of the study was to quantify the use of antiepileptic drugs (AEDs) in epilepsy and other indications in a nation-wide population using a prescription database.Materials and methodsPrescription data of AEDs were collected from the Norwegian Prescription Database for the period 2004–2007, including 5.1 million prescriptions from 144,653 patients, all having at least one prescribed and dispensed AED. Diagnosis-related reimbursement codes were used as indicators for clinical use.ResultsOf the AEDs used, 71% was in epilepsy, 15% in psychiatry, 13% in neuropathic pain, and <1% in migraine, trigeminus neuralgia and cancer adjuvance. The use in epilepsy increased steadily from 7.0 to 7.5 DDDs/1000 inhabitants/day (7%) from 2004 to 2007. The use of AEDs in other indications increased considerably more from 2004 to 2007: Neuropathic pain to 1.40 DDDs/1000 inhabitants/day (360%), psychiatry to 1.59 (200%), and migraine to 0.005 (642%). The prevalence of AED users increased and in 2007 it was 0.97% in epilepsy, 0.8% in neuropathic pain, 0.33% in psychiatry and 0.001% in migraine. In 2007, 49% of the AEDs used in epilepsy were a new drug, carbamazepine, lamotrigine and valproate being most frequently used. New AEDs were used in 96% in migraine prophylaxis, 94% in neuropathic pain, and 64% in psychiatry.ConclusionsBased on a nation-wide prescription database, this study quantifies the wide and increasing use of AEDs, in particular the newer drugs.