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carbamazepine
Apo-Carbamazepine†, Carbatrol, Novo-Carbamaz†, Tegretol, Tegretol CR†, Tegretol-XR, Tegretol Chewable Tablets, Teril‡

Pregnancy Risk Category C

How supplied
Tablets:
200 mg
Tablets (chewable):
100 mg
Tablets (extended-release)†:
100 mg, 200 mg, 400 mg
Capsules (extended-release):
200 mg, 300 mg
Oral suspension:
100 mg/5 ml

Action
Unknown. Thought to stabilize neuronal membranes and limit seizure activity by either increasing efflux or decreasing influx of sodium ions across cell membranes in the motor cortex during generation of nerve impulses.

Indications & dosage
Generalized tonic-clonic and complex partial seizures, mixed seizure patterns
--
Adults and children over age 12:
initially, 200 mg P.O. b.i.d. for tablets, or 1 teaspoon of suspension P.O. q.i.d. with meals. May be increased at weekly intervals by 200 mg P.O. daily in divided doses at 6- to 8-hour intervals. Adjusted to minimum effective level. Maximum daily dose is 1 g/day in children ages 12 to 15, and 1.2 g/day in patients over age 15. Usual maintenance dose is 800 to 1,200 mg/day.
Children ages 6 to 12:
initially, 100 mg P.O. b.i.d. or 1/2 teaspoon of suspension P.O. q.i.d. with meals, increased at weekly intervals by 100 mg P.O. daily. Maximum daily dose is 1 g/day. Usual maintenance dose is 400 to 800 mg/day.
Trigeminal neuralgia--

Adults:
initially, 100 mg P.O. b.i.d. or 1/2 teaspoon of suspension q.i.d. with meals, increased by 100 mg q 12 hours for tablets or 1/2 teaspoon of suspension q.i.d. until pain is relieved. Maximum daily dose is 1.2 g/day. Maintenance dose is 200 to 400 mg P.O. b.i.d.

Adverse reactions
CNS:
dizziness, vertigo, drowsiness, fatigue, ataxia, worsening of seizures (usually in patients with mixed seizure disorders, including atypical absence seizures), confusion, headache, syncope.
CV: heart failure,
hypertension, hypotension, aggravation of coronary artery disease, arrhythmias, AV block.
EENT:
conjunctivitis, dry mouth and pharynx, blurred vision, diplopia, nystagmus.
GI:
nausea, vomiting, abdominal pain, diarrhea, anorexia, stomatitis, glossitis.
GU:
urinary frequency, urine retention, impotence, albuminuria, glycosuria, elevated BUN levels.
Hematologic:
aplastic anemia, agranulocytosis, eosinophilia, leukocytosis, thrombocytopenia.
Hepatic:
elevated liver function test results, hepatitis.
Metabolic:
SIADH, decreased thyroid function test results.
Respiratory:
pulmonary hypersensitivity.
Skin:
rash, urticaria, erythema multiforme, Stevens-Johnson syndrome, excessive diaphoresis.
Other:
fever, chills.

Interactions
Drug-drug.
Cimetidine, danazol, diltiazem, fluoxetine, fluvoxamine, isoniazid, macrolides such as erythromycin, propoxyphene, valproic acid, verapamil: may increase carbamazepine blood levels. Use cautiously.
Doxycycline, felbamate, haloperidol, oral contraceptives, phenytoin, theophylline, warfarin:
carbamazepine may decrease blood levels of these drugs. Monitor for decreased effect.
Lithium:
increased CNS toxicity of lithium. Avoid concomitant use.
MAO inhibitors:
increased depressant and anticholinergic effects. Don't use together.
Phenobarbital, phenytoin, primidone:
may decrease carbamazepine levels. Monitor for decreased effect.
Drug-herb.
Plantains: psyllium seed has been reported to inhibit GI absorption. Avoid concomitant use.

Effects on diagnostic tests
Drug may interfere with some pregnancy tests.

Contraindications
Contraindicated in patients with hypersensitivity to carbamazepine or tricyclic antidepressants or history of previous bone marrow suppression; also contraindicated in those who have taken an MAO inhibitor within 14 days of therapy.

Nursing considerations

Patient teaching

*Liquid contains alcohol. **May contain tartrazine.  †Canada  ‡Australia  §U.K.  OTCOver the counter
Reactions may be common, uncommon, life-threatening, or COMMON AND LIFE-THREATENING

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