What is the loading dose and maintenance regimen of carbamazepine (Eptoin) for a 60‑kg adult?

Carbamazepine (Eptoin) Dosing for 60 kg Adult

For a 60 kg adult requiring carbamazepine loading, administer 480 mg (8 mg/kg) as an oral suspension as a single dose, followed by maintenance dosing of 400-800 mg daily in divided doses. 1, 2

Loading Dose Strategy

Oral suspension loading is the only validated rapid-loading approach for carbamazepine:

• Administer 8 mg/kg oral suspension (480 mg for 60 kg patient) as a single dose 1
• Achieves therapeutic serum levels within 2 hours with suspension formulation 3
• Tablets are NOT recommended for loading due to slow and erratic absorption 1
• Loading was 93% successful in achieving therapeutic levels within 3 hours 1
• No IV formulation exists for carbamazepine 1

Expected Adverse Effects with Loading

• Adverse effects occur in 58% of patients but are generally mild 1
• Most common: drowsiness (26%), nausea (23%), dizziness 1
• Less common: nystagmus, abdominal pain, vomiting, ataxia, double vision 1
• All adverse effects in loading studies were transient and well-tolerated 3

Maintenance Dosing

After loading, initiate standard maintenance therapy:

• Start with 200 mg twice daily (400 mg/day total) 2
• Increase weekly by 200 mg/day increments using 3-4 times daily dosing 2
• Target maintenance dose: 800-1200 mg daily in divided doses 2
• Maximum dose: 1200 mg/day for adults over 15 years (1600 mg/day in rare instances) 2
• Administer in at least 2-3 divided doses due to short half-life (14-16 hours) to avoid excessive peak levels 4, 3

Maintenance Dosing Considerations

• Take all doses with meals 2
• Controlled-release formulations show better compliance (90% vs 78%) 5
• Once therapeutic control achieved, reduce gradually to minimum effective level 2
• Mean effective dose typically 10-20 mg/kg/day (600-1200 mg for 60 kg adult) 5, 6

Critical Clinical Caveats

Hematologic monitoring is mandatory:

• Leukopenia occurs commonly (18% of patients) but is usually benign and transient 5
• Aplastic anemia is rare but potentially fatal, highest risk in first 3-4 months 4
• Monitor complete blood count before initiation and regularly during first 4 months 4

Drug interactions require attention:

• When adding to existing anticonvulsants, increase carbamazepine gradually while maintaining or decreasing other agents 2
• Exception: phenytoin may need to be increased due to interactions 2
• Carbamazepine induces its own metabolism (autoinduction) over 2-4 weeks 4

Therapeutic drug monitoring:

• Measure plasma levels once seizures controlled to establish individual therapeutic range 4
• Therapeutic range: 4-12 mcg/mL (though individual variation exists) 3
• Monitor both carbamazepine and its active epoxide metabolite 3

When NOT to Use Carbamazepine Loading

• If patient has history of rash with carbamazepine (8.9% incidence, requires discontinuation in 6.7%) 5
• If tablets are the only available formulation (use gradual titration instead) 1
• If patient cannot tolerate oral medications (no IV alternative exists) 1