Carbamazepine is a synthetic iminostilbene derivative structurally similar to imipramine, a tricyclic antidepressant. While unrelated structurally, carbamazepine shares a similar therapeutic action with phenytoin. Carbamazepine was first discovered in 1953 by Swiss chemist Walter Schindler. Throughout the 1960s, antimuscarinic was used and marketed for trigeminal neuralgia and as an anticonvulsant. By the 1970s, it was being used as a mood stabilizer for patients with bipolar disorder.

Uses

Carbamazepine is used in the treatment of epilepsy and trigeminal neuralgia. Unlabeled uses include treatment of postherpetic pain syndrome, neurogenic diabetes insipidus, bipolar disorder, alcohol withdrawal, and cocaine dependence.

Environmental Fate

Environmental exposure occurs via direct release into water or via vaporization into the air. It is susceptible to photolysis and is thought to have a half-life of roughly 63 days in lake water in vitro. However, when dissolved and exposed to direct photolysis, it has a half-life of approximately 1 day.

Mechanism

Carbamazepine is both an important anticonvulsant in therapeutic doses and a powerful proconvulsant in overdose. The therapeutic anticonvulsant mechanism is primarily related to blockade of presynaptic voltage-gated sodium channels. Blockade of the sodium channels is believed to inhibit the release of synaptic glutamate and possibly other neurotransmitters. Carbamazepine is also a powerful inhibitor of the muscarinic and nicotinic acetylcholine receptors, N-methyl-Daspartate (NMDA) receptors, and the central nervous system (CNS) adenosine receptors. In addition, carbamazepine is structurally related to the cyclic antidepressant imipramine and in massive overdose, it may affect cardiac sodium channels.