Dronedarone (a multichannel blocker) enhances the anticonvulsant potency of lamotrigine, but not that of lacosamide, pregabalin and topiramate in the tonic-clonic seizure model in mice.

Accumulating experimental evidence indicates that some recently licensed antiarrhythmic drugs, including dronedarone (a multichannel blocker) play a crucial role in initiation of seizures in both, in vivo and in vitro studies. Some of these antiarrhythmic drugs elevate the threshold for maximal electroconvulsions and enhance the anticonvulsant potency of classical antiepileptic drugs in preclinical studies. This study was aimed at determining the influence of dronedarone (an antiarrhythmic drug) on the anticonvulsant potency of four novel antiepileptic drugs (lacosamide, lamotrigine, pregabalin and topiramate) in the maximal electroshock-induced seizure model in mice. To exclude any potential pharmacokinetic contribution of dronedarone to the observed interactions, total brain concentrations of antiepileptic drugs were measured. Dronedarone (50 mg/kg, i.p.) significantly enhanced the anticonvulsant potency of lamotrigine, by reducing its ED value from 7.67 mg/kg to 4.19 mg/kg (P < 0.05), in the maximal electroshock-induced seizure test in mice. On the contrary, dronedarone (50 mg/kg, i.p.) did not affect the anticonvulsant properties of lacosamide, pregabalin or topiramate in the maximal electroshock-induced seizure test in mice. Measurement of total brain concentrations of lamotrigine revealed that dronedarone did not significantly alter total brain concentrations of lamotrigine in experimental animals. Additionally, the combination of dronedarone with pregabalin significantly impaired motor coordination in animals subjected to the chimney test. In contrast, the combinations of other studied antiepileptic drugs with dronedarone had no negative influence on motor coordination in mice. It is advisable to combine dronedarone with lamotrigine to enhance the anticonvulsant potency of the latter drug. The combinations of dronedarone with lacosamide, pregabalin and topiramate resulted in neutral interactions in the maximal electroshock-induced seizure test in mice. However, a special caution is advised to patients receiving both, pregabalin and dronedarone due to some possible adverse effects that might occur with respect to motor coordination.