| Abstract: | ![]()
Lamotrigine is a broad-spectrum antiepileptic drug which is thought to act in part via a use-dependent blockade of voltage-sensitive sodium channels to stabilise the neuronal membrane. This results in the inhibition of the excessive release of excitatory amino acids, such as glutamate, during epileptic activity. An open, multicentre, prospective trial of lamotrigine was carried out in adult patients with drug-resistant epilepsy on monotherapy with carbamazepine or valproate. The primary aim of the study was to assess add-on lamotrigine withdrawing to monotherapy. 28-week clinical trial was divided into 4 phases: (1) Dose escalation period (4 weeks), (2) Add-on period (8 weeks), (3) Standard AED withdrawal period (8 weeks), (4) Lamotrigine monotherapy (8 weeks). Thirty-three patients were previously treated with valproate, 44 with carbamazepine. Of 77 patients recruited into the study, 64 patients (83%) completed add-on therapy, 49 patients (64%) completed lamotrigine monotherapy. 44% of all patients during the add-on phase and 48% during lamotrigine monotherapy had a reduction in seizure frequency of at least 50% compared with pre-study period. 13% of all patients achieved seizure freedom during add-on therapy and 18% during monotherapy. Improvement of Visual Analogue Scale (VAS) scores was observed in 65% and 57% patients respectively. A significant proportion of patients could be successfully converted to lamotrigine monotherapy. Lamotrigine was also generally well tolerated. 23 patients (30%) had at least one adverse event (AE), but only 1/4 of all AEs might be reasonably regarded as an effect of the medication. 7 patients (9%) discontinued prematurely from the study due to adverse event. More AEs were observed in add-on therapy than in lamotrigine monotherapy. The safety profile was consistent with that seen during other clinical trials with lamotrigine. CONCLUSIONS: 1. Lamotrigine is effective AED in add-on and monotherapy (responders rate--44% and 48% respectively). 2. In most cases conversion from add-on therapy to monotherapy can be done successfully. 3. Lamotrigine is a safe and well-tolerated drug. |
