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Bupropion (Wellbutrin, Zyban) is unique monocyclic antidepressant and smoking cessation agent that is structurally similar to amphetamines. Bupropion blocks dopamine and norepinephrine reuptake and antagonizes acetylcholine at nicotinic receptors.
- One of the most common causes of drug-induced seizures.
- Sinus tachycardia is the most frequently seen cardiac effects with overdose.
- QTc prolongation and ventricular dysrhythmias can occur in severe overdose. New evidence supports this is not related to cardiac sodium channel block but likely due to blockade of the delayed rectifying (ikr) potassium channel and gap junction inhibition in the myocardium simulating effects class IA effect.
Bottom line:
Bupropion is a common cause of drug induced seizures but in severe overdose can also cause prolonged QTc and wide complex ventricular dysrhythmia that may be responsive to sodium bicarbonate. All patients with an overdose of bupropion should have an ECG performed and cardiac monitoring to watch for conduction delays and life-threatening arrhythmias.
References
Wide complex tachycardia after bupropion overdose. Franco V. Am J Emerg Med. 2015 Oct;33 (10):1540.
Delayed bupropion cardiotoxicity associated with elevated serum concentrations of bupropion but not hydroxybupropion. Al-Abri SA, Orengo JP, et al. Clin Tox. 2013 Dec ;51(10):1230-4.
QRS widening and QT prolongation under bupropion: a unique cardiac electrophysiological profile. Caillier B. Pilote S. et al. Fundam Clin Pharmacol. 2012 Oct;26(5): 599-608.
Comparison of Resuscitative Protocols for Bupropion Overdose Using Lipid Emulsion in a Swine Model. Fulton LV, Fabrich RA, et al, Military Medicine 181, 5:482, 2016.