ucb-34714 and carbamazepine-epoxide

To assess the effect of brivaracetam (BRV) on steady-state plasma concentrations of commonly prescribed antiepileptic drugs (AEDs).. Data were pooled from five randomized, double-blind, placebo-controlled efficacy studies (NCT00175929, NCT00175825, NCT00490035, NCT00464269, and NCT01261325) in which adults with refractory epilepsy, and receiving stable doses of 1-2 AEDs, initiated adjunctive treatment with BRV (or placebo) for up to 12 weeks, following a 4-8 week baseline period. Concentrations of carbamazepine, carbamazepine epoxide, clobazam, clonazepam, lacosamide, lamotrigine, levetiracetam, oxcarbazepine (MHD), phenobarbital, phenytoin, pregabalin, topiramate, valproic acid and zonisamide, were measured during baseline and during BRV or placebo evaluation periods. Log-transformed data for patients receiving BRV dosages of 50-200 mg/day (or placebo) were evaluated using repeated measures analysis of covariance. Geometric least-squares means ratios of respective AED concentrations (treatment vs baseline) and their 90% confidence intervals (CIs) were calculated. Relevant interaction of BRV on the respective AED was inferred if CIs were entirely outside of 0.80-1.25 limits.. Within the population for analysis (n = 1402), relevant interaction was observed for carbamazepine epoxide alone which increased up to 2-fold from baseline due to inhibition of epoxide hydrolase by BRV, and the effect size was not influenced by concomitant valproic acid. Relevant interaction was not observed for other AEDs.. In adults with focal seizures, adjunctive BRV treatment does not affect plasma concentrations of the evaluated AEDs but increases carbamazepine epoxide metabolite. Carbamazepine dose reduction should be considered if tolerability issues arise.

Topics: Adult; Anticonvulsants; Carbamazepine; Drug Resistant Epilepsy; Epilepsies, Partial; Female; Humans; Male; Middle Aged; Pyrrolidinones; Seizures

Brivaracetam (BRV) was recently introduced for the treatment of patients with focal epilepsy. BRV undergoes relatively few interactions, but one of them leads to the elevation of carbamazepine (CBZ)-10,11-CBZ-epoxide (CBZ-E) if BRV is co-administered with CBZ. This interaction has been considered to be clinically negligible. We present a case series of nine patients. In eight of them, levetiracetam (LEV) was switched to BRV. In the remaining case, oxcarbazepine was replaced by CBZ and added to a stable BRV dose. A marked increase of CBZ-E occurred in every case and was associated with clinically relevant symptoms including blurred vision, diplopia, dizziness, or fatigue in three of them. However, in the remaining six, the elevated CBZ-E levels were not associated with any tolerability problems. The importance of CBZ-E for adverse events under CBZ may have been overemphasized in the past and is not clinically impairing in most cases treated with the combination of BRV and CBZ.

Topics: Adult; Carbamazepine; Epilepsies, Partial; Female; Humans; Male; Middle Aged; Pyrrolidinones; Seizures