Peri-marketing surveillance of lamotrigine in The Netherlands: doctors' and patients' viewpoints

Evaluation of daily clinical practice in prescribing lamotrigine in refractory epilepsy patients.

A collaborative, retrospective, peri-marketing study was performed in in- and out-patients attending one of the three Dutch epilepsy centres. Analysis of both patients' and doctors' information was performed in 520 patients using questionnaires and medical files.

After one year of treatment 76% of patients maintained LTG treatment, an intention-to-treat analysis showed > = 50% seizure reduction in 23% of patients; 20-50% seizure reduction in 23% of patients. Six percent of patients became at least three months seizure free. In about 20% of patients seizures became less severe and shorter of duration, while in 6% an increase was found. After three months a significant decrease in number of concomitant antiepileptic drugs was found (change from mean 1.8 to 1.5 AEDs) (p = < 0.01). After twelve months the mean number of AEDs was 1.4 per patient. Overall percentage of side effects appeared to be significantly higher if patients' questionnaire data were used. Epilepsy patients considered side effects as an important factor in the choice of medication and in withdrawal of medication. Future developments of new AEDs should take this into account.

This perimarketing study gives insight information about long-term daily use of lamotrigine, with emphasis on effectiveness. Patients complained in the questionnaires much more about side-effects, than was known according to the medical file. Therefore, it seems necessary to perform perimarketing studies more systematically.