Bupropion overdose

• The range of bupropion overdose symptoms overlaps with that of amphetamine misuse, 3,4-methylenedioxymethamphetamines (MDMA or ecstasy) ingestion, and tricyclic antidepressant (TCA) overdose. 
• Hallucinations, agitation, and seizures are the commonest central nervous system effects after an overdose, but physical signs of anticholinergic intoxication such as mydriasis and hyperreflexia are rarely present. 
• Seizures occur in 21% of cases and up to 14 hours after overdose.
• With the exception of tachycardia, other cardiac manifestations are uncommon, but overdose with more than 1.5 g has been associated with intraventricular conduction disturbance11 and prolongation of the QTc interval.
• Arrythmias and cardiac arrest have occurred with massive overdoses; death is rare but has followed ingestion of 10 g or more.
• Treatment of an overdose of sustained release bupropion is supportive, as there is no antidote available.
• Gastric lavage and oral activated charcoal may be considered within an hour of overdose; but the value of further doses of charcoal or whole bowel irrigation in bupropion overdose has not been established. 
• Seizures are often short lived; benzodiazepines may be required for seizure control and hallucinations but antipsychotics should be avoided as these lower the seizure threshold. 
• Electrocardiographic abnormalities usually resolve without treatment although adenosine has been successfully used to treat broad complex tachycardia resulting from massive overdose.

Reference:
http://emj.bmj.com/content/20/6/560