Conversion from carbamazepine or oxcarbazepine to topiramate in adolescents and adults with epilepsy

OBJECTIVE: To explore effectiveness, tolerability and changes in quality of life in patients with epilepsy converting to topiramate (TPM) from carbamazepine (CBZ) or oxcarbazepine (OXC) due to insufficient effectiveness and/or tolerability. METHODS: A multicenter, open-label, non-interventional trial was used to examine patients (> or = 12 years) with epilepsy, changing to TPM monotherapy from baseline mono- or combination therapy with CBZ or OXC. TPM was added to the existing antiepileptic drug (AED) treatment and started at a dose of 25 mg once daily. The dose was titrated up with 25 mg/day increments, once every 1-2 weeks, until a final dose between 50 and 200 mg/day was reached. On the basis of clinical judgment, the treating physician decided whether or not the existing AED treatment with CBZ or OXC could then be withdrawn. Type and number of seizures, preferred TPM dose, quality of life (QOLIE-10 questionnaire), subjective perception of improvement and adverse events (AE) were documented. RESULTS: 140 patients (53.5% women, mean age 47 years) decided to switch to TPM due to insufficient effectiveness (75% of patients) and/or poor tolerability (80%) of the CBZ/OXC treatment. Average duration of follow-up was 24 weeks with an overall discontinuation rate of 19.3%, mainly due to AEs (12.1%). At study endpoint, the intended shift to TPM monotherapy was achieved in 73% of patients at a median TPM dose of 100 mg/day. A seizure reduction of > or = 50% was achieved in 91% of patients in the last scheduled period (weeks 12-26); 62% of patients entering that period remained seizure free. Quality of life at endpoint improved significantly when compared with baseline for all domains of QOLIE-10 (P < 0.001). Most frequent AEs (reported by > or = 5% of patients) were paresthesia (9.3%), weight loss (7.9%), convulsions (5.7%) and memory disorders (5.0%). CONCLUSION: In patients with epilepsy, previously not satisfactorily treated with CBZ or OXC, conversion to TPM may result in an improvement in seizure control as well as in quality of life.