Dosage Forms. Tablet: 200 mg; Tablet, Chewable: 100 mg; Tablet, Extended Release: 100 mg, 200 mg, 400 mg; Suspension: 100 mg/5 mL; Capsule, Extended Release: 100 mg, 200 mg, 300 mg
Common FDA Label Indication, Dosing, and Titration.
1. Bipolar disease, acute manic and mixed episodes: Extended release, 200 mg po bid, may titrate to 1600 mg/d po
2. Epilepsy, partial, generalized, and mixed types: Adults, 200 mg po bid, may titrate to 1200 mg po daily; Children <6 y, 10-20 mg/kg/d po in 2-3 divided doses, may titrate to 250-350 mg/d po; Children 6-12 y, 100 mg po bid, may titrate to 800 mg po daily
3. Trigeminal neuralgia: Regular release, 100 mg po q12h, may titrate to 1200 mg po daily prn for pain control
1. Psychotic disorder: 200-400 mg/d po in 3-4 divided doses
MOA. Carbamazepine acts presynaptically to block firing of action potentials, which decreases the release of excitatory neurotransmitters, and postsynaptically by blocking high-frequency repetitive discharge initiated at cell bodies.
Drug Characteristics: Carbamezapine
Medication Safety Issues: Carbamezapine
Drug Interactions: Carbamezapine
Adverse Reactions: Carbamezapine
Efficacy Monitoring Parameters. Reduction in number of seizures, decreased pain, therapeutic concentrations for epilepsy: 4-12 mcg/mL.
Toxicity Monitoring Parameters. Emergence or worsening of depression, suicidal behavior or ideation, or unusual changes in behavior; baseline CBC, serum sodium, LFTs, complete urinalysis, and BUN; thyroid function test at baseline and during therapy, eye examinations at baseline and during therapy.
Key Patient Counseling Points. May decrease effectiveness of oral contraceptives; use an alternative form of birth control. Avoid activities requiring mental alertness or coordination until drug effects are realized. Take with food, but not alcohol, grapefruit, or grapefruit juice. Avoid abrupt discontinuation.
Clinical Pearls. Carbamazepine is a drug of first choice for seizure disorder due to equivalent activity and decreased toxicity compared to other antiseizure medications. Suspension is dosed 3-4 times per day.