The dynamics of drug treatment in epilepsy: an observational study in an unselected population based cohort with newly diagnosed epilepsy followed up prospectively over 11-14 years

Objectives-To study prospectively long term dynamics and patterns of treatment in a population based cohort of patients with newly diagnosed epilepsy. Methods-564 patients with definite epilepsy entered the UK National General Practice Study of Epilepsy (NGPSE), between 1984 and 1987, and were prospectively followed up for between 11-14 years. Results-Treatment was started in 433 (77%) patients. Only 15% of single seizure patients had medication prescribed initially, although due to high seizure recurrence, more than 70% ultimately received antiepileptic medication. 209/564 patients (37%) were on drug therapy for epilepsy at the time of last follow up. 168/564 patients (30%) have stayed continuously on medication and another 41/564 patients (7%) restarted drug therapy because of seizure recurrence, having withdrawn medication. 98/209 (47%) of those on treatment are known to be in 5 year terminal remission. Phenytoin (29%) and carbamazepine (27%) were the most commonly preferred first line drugs followed by valproate (15%). Less than half of treated patients with partial seizures received carbamazepine as a first line drug and less than a third with generalised seizures were prescribed valproate as first choice drug. Nine out of 31 (29%) patients with one or more seizures a week at last follow up had never tried a second drug and only seven (23%) had tried four or more drugs. 11% of all treatment changes involved a new antiepileptic drug. Treatment changes were associated with low terminal remission rates. Conclusions-Out of 30 000 patients with newly diagnosed epilepsy every year in the United Kingdom, about 6000 have inadequate seizure control in the long term. About a third of the patients in this group have one or more seizures every month. Only two thirds of these patients with frequent seizures are likely to switch medication to try and achieve better seizure control. There is probably still considerable room for improvement in prescribing practice in the United Kingdom.