Rapid Oral Loading of Carbamazepine in the Emergency Department

Study Objective: This study evaluates the safety and efficacy of rapid oral loading of carbamazepine in the emergency department (ED).

Methods: Adult patients receiving maintenance carbamazepine who presented with negligible levels received an oral load of carbamazepine suspension, with a dose of 8 mg/kg.

Results: Forty-two oral loads among 36 patients were studied. Mean subject age was 36 years; 61% of the sample were male patients. The actual load administered ranged from 7.9 to 8.6 mg/kg. The mean 3-hour carbamazepine level (therapeutic 4 to 12 microg/mL) was 6.5 microg/mL (SD 2.0 microg/mL). Three patients had subtherapeutic levels after loading (successful loading rate 93%). Adverse effects occurred in 58% of patients, most commonly drowsiness (26%) and nausea (23%). Other adverse effects included dizziness, nystagmus, abdominal pain, vomiting, ataxia, and double vision. Two patients were treated for vomiting. All other adverse effects were mild and self-limited.

Conclusion: Rapid oral loading of carbamazepine in the ED in this cohort, although effective, was associated with a high rate of adverse effects. Given a sample size of 36, 95% confidence intervals suggest that the rate of serious adverse effects may be as high as 9.7% and that the rate of successful loading may be as low as 76.9%.