Immediate (overnight) switching from carbamazepine to oxcarbazepine monotherapy is equivalent to a progressive switch

This study compared immediate (overnight) and progressive switching to oxcarbazepine monotherapy in patients with partial seizures unsatisfactorily treated with carbamazepine monotherapy. Patients were randomised to either an overnight (n = 140) or a progressive switch (n = 146) from carbamazepine to oxcarbazepine monotherapy at a dose ratio of 1:1.5. The difference between the two switch groups in the mean monthly seizure frequency supported the equivalence of overnight and progressive switching (difference of 0.02 excluding outliers; 95% confidence interval (CI) -0.74, 0.78). Following the switch from carbamazepine to oxcarbazepine, there was a reduction in median monthly seizure frequency in both the overnight group (from 1.5 to 0; P = 0.0005) and the progressive group (from 1.0 to 0.4; P = 0.003). The proportion of seizure-free patients increased from 38 to 51% (P = 0.002) and 39 to 49% (P = -0.01) in the overnight and progressive groups, respectively. In addition, the proportion of patients experiencing no clinically significant adverse events did not differ between the two switch methods (difference of 2.5; 95% CI -4.1, 9.0). For patients who are unsatisfactorily treated with carbamazepine monotherapy, overnight switch to oxcarbazepine monotherapy is as effective and well tolerated as a progressive switch, therefore allowing simple and flexible individualised treatment. Switching to oxcarbazepine monotherapy appears to be beneficial for patients who are unsatisfactorily treated with carbamazepine monotherapy, independently of the switch method used.