Carbamazepine

[13][14] Photoswitchable analogues of carbamazepine have been developed to control its pharmacological activity locally and on demand using light (photopharmacology), with the purpose of reducing the adverse systemic effects of the drug.

[15] One of these light-regulated compounds (carbadiazocine, based on a bridged azobenzene or diazocine) has been shown to produce analgesia with noninvasive illumination in vivo in a rat model of neuropathic pain.

[21] In the US, the label for carbamazepine contains warnings concerning:[4] Common adverse effects may include drowsiness, dizziness, headaches and migraines, ataxia, nausea, vomiting, and/or constipation.

[26] Serious skin reactions such as Stevens–Johnson syndrome (SJS) or toxic epidermal necrolysis (TEN) due to carbamazepine therapy are more common in people with a particular human leukocyte antigen gene-variant (allele), HLA-B*1502.

[5] Odds ratios for the development of SJS or TEN in people who carry the allele can be in the double, triple or even quadruple digits, depending on the population studied.

[27][28] HLA-B*1502 occurs almost exclusively in people with ancestry across broad areas of Asia, but has a very low or absent frequency in European, Japanese, Korean and African populations.

[28][30] It is suggested that carbamazepine acts as a potent antigen that binds to the antigen-presenting area of HLA-B*1502 alike, triggering an everlasting activation signal on immature CD8-T cells, thus resulting in widespread cytotoxic reactions like SJS/TEN.

[34] By inhibiting mEH, valproic acid and valnoctamide cause a build-up of the active metabolite, prolonging the effects of carbamazepine and delaying its excretion.

Carbamazepine, as an inducer of cytochrome P450 enzymes, may increase clearance of many drugs, decreasing their concentration in the blood to subtherapeutic levels and reducing their desired effects.

[33] Drugs that are more rapidly metabolized with carbamazepine include warfarin, lamotrigine, phenytoin, theophylline, valproic acid,[18] many benzodiazepines,[35] and methadone.

[36] Carbamazepine also increases the metabolism of the hormones in birth control pills and can reduce their effectiveness, potentially leading to unexpected pregnancies.

[44][45] It was first marketed as a drug to treat epilepsy in Switzerland in 1963 under the brand name Tegretol; its use for trigeminal neuralgia (formerly known as tic douloureux) was introduced at the same time.

Taking into account only studies that used concentrations commonly found in the environment, a 2014 review concluded that "the accumulation of carbamazepine into plants grown in soil amended with biosolids poses a de minimis risk to human health according to the approach.

Tegretol 200-mg CR (made in NZ )
Metabolism. Top: carbamazepine • middle: carbamazepine-10,11- epoxide , the active metabolite • bottom: carbamazepine-10,11- diol , an inactive metabolite, which is then glucuronidized