Zeptol CR Mechanism of Action

Pharmacology: Pharmacodynamics: Mechanism of Action: The exact mechanism of action of carbamazepine is unknown. Present evidence strongly suggests that carbamazepine mediates its therapeutic effects by slowing recovery of voltage-sensitive sodium channels of neurons from inactivation. The slowed down recovery leads to prolonged inactivation and results in inhibition of neuronal repetitive firing potential. Clinically, Carbamazepine is effective as a primary drug for tonic clonic seizures, partial seizures and for non-epileptic disorders like mania and trigeminal neuralgia.
Pharmacokinetics: Upon oral administration, 72 to 96% of the dose of carbamazepine is absorbed. Maximum plasma concentrations are obtained between 6 to 24 hours following drug administration. Plasma protein binding is 75%. Volume of distribution is 2 L/kg body weight. It is extensively metabolised in the liver. Carbamazepine 10, 11 epoxide is an active metabolite. 1% is excreted unchanged in urine. Elimination half-life is 30 to 40 h. Carbamazepine is an enzyme inducer in the liver and hence several drug interactions may occur. Steady state levels are 4-12 mcg/ml while toxicity appears at 15 mcg/ml and above. Carbamazepine crosses placenta and is secreted into breastmilk.