Carbamazepine
General
- Type: Anticonvulsant, antimanic
- Dosage Forms:tablet (chewable, immediate-release, ER), capsule (ER), oral suspension
- Dosage Strengths: chewable tablet: 100mg; immediate-release tablet: 200mg; extended-release tablet: 100, 200, 400mg; extended-release capsule: 100, 200, 300mg; oral suspension: 100mg/5mL; IV solution: 10mg/mL
- Routes of Administration: PO, IV
- Common Trade Names: Tegretol, Equetro, Epitol, Tegretol XR, Carbagen SR, Carbatrol, Teril, Carnexiv
Adult Dosing
- Maintenance dose:800-1200mg/day PO in divided doses
- Therapeutic range: 4-12mg/L (16.9-50.8 micromoles/L)
- Max dose: 1600mg/day (rarely 1.6-2.4g/day)
- Maintenance dose: 400-800mg/day PO in divided doses
- Max dose: 1200mg/day
Bipolar Mania
- Initial 200mg PO q 12h increase by 200mg/day
- Max dose 1600mg/day
Restless legs syndrome (off label)
- 100-600mg PO qHS up to 5 weeks
Schizophrenia (off label)
- 200-1300mg/day for 2.5-8 weeks
Postherpatic Neuralgia (off label)
- 100-200mg PO qDay, may increase slowly to 1200mg/day
Pediatric Dosing
Epilepsy
<6 years old
- Initial: tablet- 10-20mg/kg/d PO q8-12h, suspension-10-20mg/kg/d PO q6h
- Maintenance: may divide frequency into 3-4 times daily not to exceed 35mg/kg/day
>6 years old
- Inital: suspension- 50mg PO q6h, tablet- 100mg PO q12h, may increase q week by 100mg/day
- Maintenance: 400-800mg/day PO q6-8h (immediate release), q12h (ER)
>12 years old
- Initial: suspension- 10mL (200mg) PO q6h; tablet- 200mg PO q12h, may increase qWeek q12h (ER); q6-8h (other formulations)
Special Populations
- Pregnancy Rating: D
- Lactation: Enters breast milk; not recommended
- Renal Dosing
- Adult: GFR<10: 75% of dose and monitor
- Pediatric: same
- Hepatic Dosing
- Adult: Use caution, drug primarily metabolized in live
- Pediatric: same
Contraindications
- Allergy to class/drug
- History of bone marrow suppresion
- MAOI use within last 14d
- coadministration with nefazodone, NNRTIs
- Jaundice, hepatitis
- Pregnancy, especially 1st trimester
Adverse Reactions
Serious
- Toxic epidermal necrolysis and Stevens Johnson syndrome especially in Asian populations
- Aplastic anemia and agranulocytosis
- Hyponatremia
Common
Ataxia, Dizziness, Drowsiness, Nausea, Vomiting, Dry mouth
Pharmacology
- Half-life: 25-65 hr (initial dosing), 10-20 hr after autoinduction; 35-40h (extended release)
- Metabolism: hepatic CYP3A4
- Excretion: Urine (72%), Feces (28%)
- Mechanism of Action: stabilizes inactivated state of sodium channels, making neurons less excitable