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 μg/mL) was 6.5 μg/mL (SD 2.0 μg/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%.