Cytisine inhibits the anticonvulsant activity of phenytoin and lamotrigine in mice

Cytisine (CYT), the most commonly used drug for smoking cessation in Poland, was experimentally found to induce convulsions. There is a lack of studies on the influence of CYT on the anticonvulsant activity of antiepileptic drugs (AEDs). The effects of CYT on the anticonvulsant activity of six AEDs were examined in maximal electroshock (MES)-induced seizures in mice. Single intraperitoneal (ip) administration of CYTin a subthreshold dose of 2mg/kg antagonized the protective activity of ip phenytoin and lamotrigine against MES-induced seizures in mice. Adose of 1mg/kg did not reverse the protective activity of phenytoin and lamotrigine. CYT in a dose of 2mg/kg had no effect on the anticonvulsive activity of carbamazepine, oxcarbazepine, phenobarbital, and valproate magnesium. CYT ability to antagonize the anticonvulsive activity of phenytoin and lamotrigine can be of serious concern for epileptic smokers, who might demonstrate therapeutic failure to these drugs resulting in possible breakthrough seizure attacks.