Carbamazepine

Carbamazepine primarily acts by stabilizing the inactivated state of voltage-gated sodium channels in neuronal membranes, thereby inhibiting repetitive firing of action potentials. This reduces the propagation of abnormal electrical impulses in the brain. It may also affect calcium channels and enhance central noradrenergic and serotonergic transmission.

Adult

Epilepsy: Initial 200 mg twice daily (immediate-release) or 100 mg twice daily (extended-release). Increase by 200 mg/day at weekly intervals to a maintenance dose of 800-1200 mg/day in 2-4 divided doses. Max 1600 mg/day.Trigeminal Neuralgia: Initial 100 mg twice daily. Increase by 100 mg every 12 hours until pain relief, typically 400-800 mg/day.…

Pediatric

Epilepsy (≥6 years): Initial 100 mg twice daily or 10 mg/kg/day in 2-3 divided doses. Increase by 100 mg/day weekly to 400-800 mg/day; Max 1000 mg/day (for children 6-12 years). Children >12 years follow adult dosing.

Renal adjustment

No specific dose adjustment recommended for mild-moderate renal impairment. Use with caution in severe renal impairment (CrCl <10 mL/min). Carbamazepine and its active metabolite are dialyzable; supplemental doses may be required post-dialysis.

Hepatic adjustment

Use with caution. Dose reduction may be necessary in severe hepatic impairment. Liver function tests should be monitored regularly.

Geriatric

Initiate with lower doses (e.g., 100 mg twice daily) and titrate slowly due to increased sensitivity to adverse effects (e.g., dizziness, ataxia, hyponatremia) and potential for drug interactions. Careful monitoring is essential.

Max dose

Generally 1200-1600 mg/day (for epilepsy).

• Hypersensitivity to carbamazepine or tricyclic antidepressants
• History of bone marrow depression
• Concomitant use with monoamine oxidase inhibitors (MAOIs) or within 14 days of discontinuing MAOIs
• History of hepatic porphyria
• Concomitant use with delavirdine (due to CYP3A4 inhibition)
• Severe cardiac conduction abnormalities
• HLA-B*1502 allele positive patients (genetic screening recommended for Asian ancestry due to serious skin reactions)
• cannot be loaded or rapidly titrated (due to adverse effects like dizziness or ataxia)
• clozapine (due to rare bone marrow effects)
• Combined with alcohol use
• diabetic neuropathic pain
• traumatic neuropathic pain
• other forms of neuropathic pain