Shire, patent expires 2011. Generic carbamazepine (immediate release) is available.
FDA approved in 2004 for the treatment of acute manic or mixed manic episodes.
Supplied in 100 mg, 200 mg, and 300 mg capsules. (Equetro’s competitor Tegretol XR, approved for epilepsy but not for bipolar disorder, is available as 100 mg, 200 mg, and 400 mg tablets.)
Usual starting dose is 200 mg BID, gradually increasing up to an average effective dose of 400 mg BID. The maximum recommended dose is 1600 mg QD (split BID).
Dose should be decreased in elderly, hepatic impairment and renal impairment.
Common side effects that occur at a rate greater than placebo: dizziness (44%), sedation (32%), nausea (29%), vomiting (18%), ataxia (15%).
Carbamazepine is associated with aplastic anemia and agranulocytosis at a rate 5 to 8 times greater than the general population (the baseline population rate is about 5/1,000,000.) Liver damage also possible.
Stevens-Johnson Syndrome (a blistering flat rash that may affect the mucous membranes) occurs in about 1/5,000 patients, a rate similar to that of Lamictal.
In one of the two major FDA studies, caused higher cholesterol than placebo.
Does not cause clinically significant weight gain.
Pregnancy Category D (risk of spina bifida).
3A4 inhibitors can increase Equetro levels, including grapefruit juice, Prozac, Luvox, and nefazodone.
Decreases Lamictal levels by 40%.
Induces 3A4, so can decrease levels of oral contraceptives and warfarin.
Caution when combining with Lithium—can increase neurotoxic side effects.
Absorption is faster when taken with food.
Equetro induces its own metabolism, meaning that serum levels decrease after about a week of administration.
Half life varies with the induction of its own metabolism, but eventually averages to around 15 hours.