What is carbamazepine, and how does it work (mechanism of action)?
Carbamazepine is an anti-seizure medication.
Recurrent seizures (epilepsy)
are divided into two main categories according to how much of the brain is
involved, either partial or
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 by
nerves in the brain. It also is used for treating
trigeminal
neuralgia. One dosage form, Equetro, has been approved for treating
bipolar
disorder. The FDA approved carbamazepine in March 1968.
What brand names are available for carbamazepine?
Tegretol, Tegretol XR , Equetro, Carbatrol, Epitol, Teril
Is carbamazepine available as a generic drug?
GENERIC AVAILABLE: Yes
Do I need a prescription for carbamazepine?
Yes
What are the side effects of carbamazepine?
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.
Rarely, patients with Asian ancestry 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 patients who are Asian
before starting therapy.
Antiepileptic medications have been associated with an 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.
What is the dosage for carbamazepine?
Carbamazepine may be taken with or without food. Carbamazepine is
excreted by the kidney and eliminated by the liver, and dosages may need to be
lowered in patients with liver or kidney dysfunction. Blood levels of
carbamazepine are used for adjusting dosing. The dose for seizures is 800 to
1600 mg daily in divided doses. Trigeminal neuralgia is treated with 400-1200 mg
daily in divided doses. The dose for treating bipolar disorder using Equetro is
begun at 200 mg every 12 hours initially, and then increased by 200 mg a day up
to a maximum dose of 1600 mg per day.
Which drugs or supplements interact with carbamazepine?
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 eliminated with carbamazepine, while carbamazepine levels are elevated when taken with erythromycin, cimetidine (Tagamet), propoxyphene (Darvon), and calcium channel blockers. Carbamazepine also increases the elimination 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.
Is carbamazepine safe to take if I’m pregnant or breastfeeding?
If possible, carbamazepine should not be used in pregnancy
or while breastfeeding.
What else should I know about carbamazepine?
What preparations of carbamazepine are available?
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
How should I keep carbamazepine stored?
Carbamazepine should be stored in a tight, light resistant container
at room temperature.