Antiepileptic

Carbamazepine 200 mg, n50

International Nonproprietary Name (INN): Carbamazepine

Pharmaceutic group: Antiepileptic

Presentation:

Tablets 200 mg n50.

Available with prescription

Question?

THERE ARE CONTRAINDICATIONS. CAREFULLY READ THE INSTRUCTIONS FOR USE, OR OBTAIN A SPECIALIST ADVICE

Carbamazepine (CBZ) is an anticonvulsant and mood-stabilizing drug used primarily in the treatment of epilepsy and bipolar disorder, as well as trigeminal neuralgia. It is also used off-label for a variety of indications, including attention-deficit hyperactivity disorder (ADHD), schizophrenia, phantom limb syndrome, complex regional pain syndrome, paroxysmal extreme pain disorder, neuromyotonia, intermittent explosive disorder, borderline personality disorder and post-traumatic stress disorder.

It has been seen as safe for pregnant women to use carbamazepine as a mood stabilizer, but, like other anticonvulsants, intrauterine exposure is associated with spina bifida and neurodevelopmental problems.

Carbamazepine is typically used for the treatment of seizure disorders and neuropathic pain. It may be used as a second line treatment for bipolar disorder and along with antipsychotic agents in schizophrenia.

HISTORY. Carbamazepine was discovered by chemist Walter Schindler at J.R. Geigy AG (now part of Novartis) in Basel, Switzerland, in 1953. Schindler then synthesized the drug in 1960, before its anti-epileptic properties had been discovered.

Carbamazepine was first marketed as a drug to treat trigeminal neuralgia (formerly known as tic douloureux) in 1962. It has been used as an anticonvulsant in the UK since 1965, and has been approved in the U.S. since 1974.

In the United States, the FDA-approved indications are epilepsy (including partial seizures and tonic-clonic seizures), trigeminal neuralgia, and manic and mixed episodes of bipolar I disorder. Although data are still lacking, carbamazepine appears to be as effective and safe as lithium for the treatment of bipolar disorder, both in the acute and maintenance phase.

In 1971, Drs. Takezaki and Hanaoka first used carbamazepine to control mania in patients refractory to antipsychotics (Lithium was not available in Japan at that time). Dr. Okuma, working independently, did the same thing with success. As they were also epileptologists, they had some familiarity with the anti-aggression effects of this drug. Carbamazepine would be studied for bipolar disorder throughout the 1970s.

MECHANISM OF ACTION. The mechanism of action of carbamazepine and its derivatives is relatively well understood. Voltage-gated sodium channels are the molecular pores that allow brain cells (neurons) to generate action potentials, the electrical events that allow neurons to communicate over long distances. After the sodium channels open to start the action potential, they inactivate, in essence closing the channel. Carbamazepine stabilizes the inactivated state of sodium channels, meaning that fewer of these channels are available to subsequently open, making brain cells less excitable (less likely to fire). Carbamazepine has also been shown to potentiate GABA receptors made up of alpha1, beta2, gamma2 subunits.