Carbamazepine (Tegretol) is an anticonvulsant that has been used extensively off label for a number of years as a mood stabilizer. In 2005, the extended-release (ER) form of this medication (Equetro) received FDA approval for the treatment of acute manic and mixed episodes.
While still widely used both alone and in combination with other medications, it is rarely a first-line choice on account of its side effect profile, which includes the risk of a serious bleeding condition in which the body stops producing white blood cells needed to fight infection (agranulocytosis). As a result, blood tests are recommended, especially when starting this medication.
Carbamazepine is metabolized in the liver and has a half life that starts out long (twenty-five to sixty-five hours) but then decreases as it has the unique ability to increase its own metabolism, as well as that of many other drugs. Women taking carbamazepine need to know that it increases the breakdown of oral contraceptives (birth control pills) increasing the risk of an unplanned pregnancy. An alternative means of birth control, or a higher dose oral contraception, is strongly advised.