A Cochrane review included 9 studies with a total of 2572 subjects. A total of 88% of included individuals experienced partial onset seizures at baseline. For remission outcomes, a HR < 1 indicated an advantage for carbamazepine and for first seizure and withdrawal outcomes a HR < 1 indicated an advantage for lamotrigine. The time to withdrawal of allocated treatment (HR 0.71, 95% CI 0.62 to 0.82; 9 trials, n=2481), time to first seizure (HR 1.22, 95% CI 1.09 to 1.37; 9 trials, n=2564) and time to 6-month remission (HR 0.84, 95% CI 0.74 to 0.94; n=1793), showing a significant advantage for lamotrigine compared to carbamazepine for withdrawal but a significant advantage for carbamazepine compared to lamotrigine for first seizure and 6-month remission. There was no difference between the drugs for time to 12-month remission (HR 0.91, 95% CI 0.77 to 1.07; 2 trials, n=998) or time to 24-month remission (HR 1.00, 95% CI 0.80 to 1.25; one trial, n=755). The most commonly reported adverse events for both of the drugs were dizziness, fatigue, gastrointestinal disturbances, headache and skin problems. The rate of adverse events was similar across the two drugs.
Comment: The quality of evidence is downgraded by inconsistency (heterogeneity in studied patients, treatments and outcomes).