Carbamazepine Uses, Side Effects, and More

 Carbamazepine

Brand name:- Tegretol, Mazetol, Carbazole, Mazetol sr , Tegrital Cr 200,400mg tab.

Carbamazepine is an anticonvulsant used to treat various types of seizures and pain resulting from trigeminal neuralgia.

Pharmacodynamic:- 

General effects 

Carbamazepine treats seizures and the symptoms of trigeminal neuralgia by inhibiting sodium channels. In bipolar  1 disorder, carbamazepine has been found to decrease mania symptoms in a clinically significant manner according to the Young Mania Rating Scale (YMRS).Carbamazepine has a narrow therapeutic index.

A note on genetic variation and carbamazepine use

In studies of Han Chinese ancestry patients, a pronounced association between the HLA-B*1502 genotype and Steven Johnson syndrome and/or toxic epidermal necrolysis (SJS/TEN) resulting from carbamazepine use was observed.

Pharmacokinetics:- 

Oral absorption of carbamazepine is slow and variable because of poor water solubility. It is 75% bound to plasma proteins and metabolized in liver by oxidation to an active metabolite ( 10-11 epoxy carbamazepine) as well  as by hydroxylation and conjugating to inactive ones . It is a substrate as well as inducer of CYP3A4 and CYP2C9. 

Initially it's plasma t½ is 20-40 hours but, decrease to 10-20hr on chronic medication due to autoinduction of metabolism.

Mechanism of action:- 

Carbamazepine is a sodium channel blocker.[34] It binds preferentially to voltage-gated sodium channels in their inactive conformation, which prevents repetitive and sustained firing of an action potential. Carbamazepine 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.[35][36][37] It has been suggested that carbamazepine can also block voltage-gated calcium channels, which will reduce neurotransmitter release. 

Used:-

used to prevent and control seizures. This medication is known as an anticonvulsant or anti-epileptic drug. It is also used to relieve certain types of nerve pain (such as trigeminal neuralgia). 

 side effects:- 

Nausea, vomiting, dizziness, drowsiness, constipation, dry mouth, or unsteadiness may occur

Dose:- 200-400mg TDS ; Children 15-30mg/kg/day. As directed by your doctor.