Abstracts

Lamotrigine (LMG) is a broad spectrum antiepileptic drug (AED) and is effective in both partial and generalized seizures. We evaluated the changes in seizure frequency and adverse effect profile after adding LMG to another AED, converting from another AED to LMG, or initiating LMG monotherapy in a general epileptic population.
We conducted a retrospective record review of patients receiving LMG therapy for at least 4 months as monotherapy or combination therapy and had well documented new onset or refractory partial epilepsy (PE) or primary generalized epilepsy (PGE). We collected data regarding the patient[rsquo]s age, epilepsy classification, type and frequency of seizures at baseline and following LMG administration, number of failed AEDs, LMG dose as monotherapy or polytherapy, and adverse side effects. Statistical analysis was performed with t-test, Wilcoxon-signed rank test for numeric and chi-square for nominal variables. Logistic regression analysis was also done with seizure freedom as the dependent variable.
Data on 68 consecutive patients (36 females and 32 males, mean age 37.7 [plusmn] 13.5 years) were collected. One patient withdrew from the study due to rash (1.5%) and data of 67 patients were analyzed. Seventeen patients had PGE and 50 PE. LMG was prescribed as monotherapy or conversion to monotherapy in 20 patients and as adjunctive therapy in 47 patients, with mean follow up of 25 months (range 4[ndash]84 months). LMG dose was not different in monotherapy vs polytherapy (p = 0.27). Patients had failed a mean of 2.65 AEDs prior to LMG (0[ndash]7 AEDs). All 8 patients with PGE on monotherapy and 2 of 9 patients (22%) on polytherapy became seizure free. Ten of 12 patients (83%) with PE on monotherapy and 8 of 38 (21%) on polytherapy became seizure free. Monotherapy and the number of failed AEDs prior to LMG were independently associated with seizure freedom (odds ratio, 95% CI 1.75, 3.2[ndash]100, p [lt] 0.001 and 0.63, 0.4[ndash]0.99, p [lt] 0.05, respectively) in a logistic regression model. One patient with PE on monotherapy had unchanged seizure frequency and another increase by 20%. Thirty three patients on polytherapy (6 with PGE and 27 with PE) had decreased seizure frequency [% mean reduction: simple partial seizures 53%, p = 0.005, complex partial 47.3%, p = 0.002, generalized tonic-clonic 62%, p = 0.03, Wilcoxon signed ranks test] and 4 had increased frequency (1 with primary and 3 with partial epilepsy). The most common side effects were double vision (12%), rash (6%) and headache (4.5%). LMG was discontinued in only one case.
Our results suggest reduction or freedom from seizures in 92.5% of patients with PGE or PE. Monotherapy with LMG independently led to seizure freedom. Although patients on previous polytherapy were less likely to become seizure free, LMG led to seizure frequency reduction. Side effects were reported in 4-12% of patients, but were well tolerated.