<unk>  inhibits CYP2C9, glucuronyl transferase, and epoxide hydrolase and is highly protein bound and hence may interact with drugs that are substrates for any of these enzymes or are highly protein bound themselves. It may also potentiate the CNS depressant effects of alcohol. It should not be given in conjunction with other antiepileptics due to the potential for reduced clearance of other antiepileptics (including carbamazepine, lamotrigine, phenytoin and phenobarbitone) and itself. It may also interact with: * Aspirin: may increase<unk>  concentrations. May also interfere with<unk> 's metabolism. * Benzodiazepines: may cause CNS depression and there are possible pharmacokinetic interactions. * Carbapenem antibiotics: reduce<unk>  levels, potentially leading to seizures. * Cimetidine: inhibits<unk> 's metabolism in the liver, leading to increased<unk>  concentrations. * Erythromycin: inhibits<unk> 's metabolism in the liver, leading to increased<unk>  concentrations. * Ethosuximide:<unk>  may increase ethosuximide concentrations and lead to toxicity. * Felbamate: may increase plasma concentrations of<unk> . * Mefloquine: may increase<unk>  metabolism combined with the direct epileptogenic effects of mefloquine. * Oral contraceptives: may reduce plasma concentrations of<unk> . * Primidone: may accelerate metabolism of<unk> , leading to a decline of serum levels and potential breakthrough seizure. * Rifampicin: increases the clearance of<unk> , leading to decreased<unk>  concentrations * Warfarin:<unk>  may increase free warfarin concentration and prolong bleeding time. * Zidovudine:<unk>  may increase zidovudine serum concentration and lead to toxicity.
Valproate
Tiagabine
Retigabine
Lamotrigine
Felbamate
Topiramate
Mesuximide
Primidone