(139) Single-Agent Bupropion Overdose Presenting as Serotonin Syndrome: A Case Report and Literature Review

Abstract:

Introduction:

Bupropion is a dopamine norepinephrine reuptake inhibitor (DNRI) felt to work in the mesocorticolimbic pathway (Ghanbari, 2011). Overdose generally causes tachycardia, tremor, hallucinations, seizures, and agitation (Sidlak, 2020). Although not directly serotonergic, bupropion has indirect effects on serotonergic neurons through inducing increased norepinephrine release in the raphe nucleus and locus coeruleus (Ghanbari, 2011). Theoretically, this could cause symptoms more consistent with serotonin toxicity than simply dopamine and norepinephrine toxicity. Here, we present a case of a man who overdosed on bupropion with signs of serotonin syndrome.




Case:

Mr. P is a 20-year-old man with a history of major depressive disorder who presented to the emergency department having ingested 22 tablets of Wellbutrin XL 150mg. EKG, CK, CMP, and CBC were normal with a negative urine drug screen. At hour 9, the patient exhibited tachycardia, confusion, slurred speech, and agitation, followed by a seizure aborted with Ativan. On follow-up exam at hour 17, the patient had tachycardia, confusion, agitation, dry lips and tongue, sustained clonus bilaterally, myoclonus, and 4+ reflexes with contralateral and ipsilateral spread, meeting Hunter Serotonin Toxicity Criteria. Agitation was managed with benzodiazepines. The following day, the patient was at baseline mentation with decreased clonus and hyperreflexia. He was transferred to an inpatient psychiatric hospital for further treatment.




Discussion:

There is little literature on single agent bupropion overdose resulting in serotonin syndrome. There were 3 articles located with a total of 9 patients who, in combination, presented with the following: 77.8% agitation, 88.9% clonus, 44.4% seizures, and 55.6% tremors (Sidlak, 2020; Murray, 2021; Thorpe, 2010). One hundred percent of the cases met Hunter’s Criteria. Treatment included cyproheptadine, a 5HT1A and 5HT2A antagonist, and benzodiazepines.



Conclusions/Implications:

As bupropion is known by most psychiatrists as a pure DNRI to both augment serotonin reuptake inhibitors and use in individuals who have side effects from serotonin, it is uncommon to consider that bupropion itself could cause serotonin toxicity in overdose. Psychiatrists need to be aware of this rare but possible complication in single agent overdose.




References:



1. Ghanbari R, El Mansari M, Blier P: Enhancement of serotonergic and noradrenergic neurotransmission in the rat hippocampus by sustained administration of bupropion. Psychopharmacology (Berl) 2011; 217, 61–73 .

2. Sidlak A, Koivisto K, Marino R, Abesamis M: Serotonin toxicity from isolated bupropion overdoses. Clinical Toxicology 2020; 58, 1347–1349.

3. Murray B, Carpenter J, Sayers J, Yeh M, Beau J, Kiernan E, Wolf M, Bolton T, Kazzi Z: Two Cases of Serotonin Syndrome After Bupropion Overdose Treated With Cyproheptadine. The Journal of Emergency Medicine 2021; 60, 67–71.

4. Thorpe E, Pizon A, Lynch M, Boyer J: Bupropion Induced Serotonin Syndrome: A Case Report. Journal of Medical Toxicology 2010; 6, 168–171.