Adults

Initial 200 mg orally twice daily, gradually increased by 200 mg/day at weekly intervals to an effective dose, usually 800-1200 mg/day in divided doses (e.g., 400-600 mg twice daily for CR). Max 1600 mg/day.

Elderly

Lower initial doses (e.g., 100 mg twice daily) and slower titration recommended due to increased sensitivity and potential for adverse effects.

Renal_impairment

No specific dose adjustment for mild to moderate impairment; caution needed in severe impairment. Monitor plasma levels.

Onset

Acute effect for some neuropathic pain within hours; full therapeutic effect for epilepsy or mood stabilization may take days to weeks.

Excretion

Mainly renal (72% as metabolites); some fecal excretion (28%).

Half life

Initial single dose half-life is 25-65 hours; with chronic administration, autoinduction of metabolism leads to a half-life of 12-17 hours.

Absorption

Slow and variable absorption from CR formulation, peak plasma levels typically reached in 4-8 hours, but can be up to 24 hours. Food can increase absorption.

Metabolism

Extensively metabolized in the liver, primarily by CYP3A4, to an active metabolite, carbamazepine-10,11-epoxide.

Warfarin

Reduced anticoagulant effect due to enzyme induction; monitor INR closely.

MAO Inhibitors

Risk of hypertensive crisis; do not use concurrently or within 14 days.

Oral Contraceptives

Reduced efficacy of contraceptives due to enzyme induction; consider alternative contraception.

Other Antiepileptics (e.g., Phenytoin, Phenobarbital)

Altered plasma levels of both carbamazepine and co-administered drugs; requires careful monitoring.