Incidence and onset of delayed seizures after overdoses of extended-release bupropion.

BACKGROUND Delayed seizures have been reported with overdoses of bupropion extended-release (XL). This study systematically evaluates the frequency and timing of seizures and an association between other toxic effects (ie, agitation, tremors, and hallucinations) and seizures. METHODS A 3-year multi-poison center observational study of hospitalized patients with ingestion of bupropion XL >or=600 mg in adults and >or=4 mg/kg in children was performed. Patients with coingestants or a medical history that could affect seizure occurrence were excluded. Data collection forms captured onset time of seizure(s), other symptoms, and treatment. RESULTS One hundred seventeen patients met inclusion criteria: median age of 22 years (range, 1.3-65 years) with 16 children 8 hours. Subsequent seizures occurred in 49%. Children ages 1.3, 3, and 7 years, developed seizures. In patients >or= 13 years of age, median dose with seizures was 4350 mg (range, 600-54 000) compared to 2400 mg (range, 600-9000) in patients without seizures. Agitation, tremors, and hallucinations occurred in 29.7%, 40.5%, and 18.9% of patients with seizures, respectively, compared with 12.5 %, 17.5%, and 10% in patients without seizures. The neurologic effects agitation (P = .045) and tremors (P = .005) occurred more frequently. CONCLUSION Delayed seizure onset suggests a minimum observation period of 24 hours after bupropion XL overdose. Although patients experiencing agitation or tremors may be at greater risk, seizures can occur without preceding central nervous system toxicity.