Mechanism of action<unk>  is a sodium channel blocker. It binds preferentially to voltage-gated sodium channels in their inactive conformation, which prevents repetitive and sustained firing of an action potential.<unk>  has effects on serotonin systems but the relevance to its antiseizure effects is uncertain. There is evidence that it is a serotonin releasing agent and possibly even a serotonin reuptake inhibitor. It has been suggested that<unk>  can also block voltage-gated calcium channel, which will reduce neurotransmitter release. Pharmacokinetics Metabolism. Top:<unk>  • middle:<unk> -10,11-epoxide, the active metabolite • bottom:<unk> -10,11-diol, an inactive metabolite, which is then glucuronidized<unk>  is relatively slowly but practically completely absorbed after administration by mouth. Highest concentrations in the blood plasma are reached after 4 to 24 hours depending on the dosage form. Slow release tablets result in about 15% lower absorption and 25% lower peak plasma concentrations than ordinary tablets, as well as in less fluctuation of the concentration, but not in significantly lower minimum concentrations. 20 to 30% of the substance are circulating in form of<unk>  itself, the rest are metabolites. 70 to 80% are bound to plasma proteins. Concentrations in the breast milk are 25 to 60% of those in the blood plasma.<unk>  itself is not pharmacologically active. It is activated, mainly by CYP3A4, to<unk> -10,11-epoxide, which is solely responsible for the drug's anticonvulsant effects. The epoxide is then inactivated by microsomal epoxide hydrolase (mEH) to<unk> -trans-10,11-diol and further to its glucuronides. Other metabolites include various hydroxyl derivatives and<unk> -N-glucuronide. The plasma half-life is about 35 to 40 hours when<unk>  is given as single dose, but it is a strong inducer of liver enzymes, and the plasma half-life shortens to about 12 to 17 hours when it is given repeatedly. The half-life can be further shortened to 9–10 hours by other enzyme inducers such as phenytoin or phenobarbital. About 70% are excreted via the urine, almost exclusively in form of its metabolites, and 30% via the faeces.
Carbamazepine
Oxcarbazepine
Capsazepine
Propazepine
Nitroxazepine
Eslicarbazepine acetate
Phenytoin
Lamotrigine