Pharmacy Author: Emmanuel Saltiel, PharmD, FASHP, FCCP
Pharmacy and Medical Editor: Jay W. Marks, MD

GENERIC NAME: carbamazepine

BRAND NAME: Tegretol, Tegretol XR , Equetro, Carbatrol

DRUG CLASS AND MECHANISM: Carbamazepine is an anti-seizure medication. Recurrent seizures (epilepsy) are divided into two main categories according to how much of the brain is involved, partial and generalized epilepsy (which includes petit mal, grand mal, and myoclonic epilepsy). Seizures are called "simple" if there is no loss of consciousness and "complex" if there is. Medicines that inhibit seizures are called anti-convulsants. Carbamazepine works as an anti-convulsant for partial and grand mal seizures by reducing or blocking certain responses in the brain. It is also used for treating trigeminal neuralgia. One dosage form, Equetro, has been approved for treating bipolar disorder.

PRESCRIPTION: yes

GENERIC AVAILABLE: yes

PREPARATIONS: Tablets: 200 mg. Chewable tablets; 100 mg. Extended release tablets; 100, 200, and 400 mg. Suspension; 100 mg/5 ml. Equetro is available in 100, 200, and 300 mg extended release tablets

STORAGE: Carbamazepine should be stored in a tight, light resistant container at room temperature.

PRESCRIBED FOR: Carbamazepine is used in the treatment of simple and complex partial seizures and in generalized seizures of the grand mal type. It is not used to treat petit mal seizures. Carbamazepine also is used to treat a painful nerve condition of the face called trigeminal neuralgia. Equetrol is used to treat bipolar disorder.

DOSING: Carbamazepine may be taken with or without food. Carbamazepine is excreted by the kidney and metabolized by the liver and dosages may need to be lowered in patients with liver or kidney dysfunction. Drug blood levels of carbamazepine can be followed.

DRUG INTERACTIONS: Carbamazepine interacts with multiple drugs and caution should be used in combining other medicines with it. Lower levels of carbamazepine are seen when administrated with phenobarbital, phenytoin (Dilantin), or primidone (Mysoline). Warfarin (Coumadin), phenytoin (Dilantin), theophylline, and valproic acid (Depakote, Depakote ER, Depakene, Depacon) are more rapidly metabolized with carbamazepine, while carbamazepine levels are elevated when taken with erythromycin, cimetidine (Tagamet), propoxyphene (Darvon), and calcium channel blockers. Carbamazepine also increases the metabolism (destruction) of the hormones in birth control pills and can reduce the effectiveness of birth control pills. Unexpected pregnancies have occurred in patients taking both carbamazepine and birth control pills.

PREGNANCY: If possible, carbamazepine should not be used in pregnancy or while breastfeeding.

NURSING MOTHERS: If possible, carbamazepine should not be used in pregnancy or while breast feeding.

SIDE EFFECTS: Serious side effects include dangerously low red and white blood cell counts. Severe skin reactions can occur as well as serious liver abnormalities, such as hepatitis, resulting in jaundice. Low sodium levels and thyroid abnormalities have been described. Minor more common side effects include dizziness, unsteadiness, nausea, and vomiting. Rare patients with Asian ancestry rarely may develop severe skin reactions to carbamazepine (Stevens-Johnson syndrome and toxic epidermal necrolysis). These patients can be identified by genetic testing, and such testing is recommended for all Asian patients before starting therapy.

Antiepileptic medications have been associated with increased risk of suicidal thinking and behavior. Anyone considering the use of antiepileptic drugs must balance this risk of suicide with the clinical need. Patients who are started on therapy should be closely observed for clinical worsening, suicidal thoughts, or unusual changes in behavior.

Last Editorial Review: 1/23/2008

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