SHM Converge Scientific Abstract ePoster Gallery-Serotonin Syndrome in an Elderly Patient Following Combined Use of Venlafaxine and Trazodone: A Case Report

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This case report describes serotonin syndrome in a 70-year-old woman who developed symptoms after starting venlafaxine while already taking trazodone. She presented to the emergency department with confusion, agitation, nausea, vomiting, diaphoresis, fever, tremors, muscle rigidity, diarrhea, severe hypertension, tachycardia, and atrial fibrillation. On examination, she had disorientation, hyperreflexia, inducible clonus, mydriasis, agitation, and rigors. Laboratory testing was largely unremarkable aside from elevated lactate, and other causes such as infection or toxic exposure were not strongly supported.<br /><br />Serotonin syndrome is a potentially life-threatening condition caused by excess serotonergic activity, often due to medication interactions, polypharmacy, or overdose. It is diagnosed clinically, with the Hunter Serotonin Toxicity Criteria being the most sensitive and specific tool. Common triggers include SSRIs, SNRIs, MAOIs, tricyclic antidepressants, linezolid, and certain other serotonergic drugs. Even medications considered relatively low risk, such as trazodone, can contribute when combined with other serotonergic agents.<br /><br />In this case, the diagnosis was made clinically using the Hunter criteria. Treatment included stopping serotonergic medications, IV fluids, external cooling, lorazepam for agitation and neuromuscular symptoms, and cyproheptadine. The patient improved within 24–48 hours, with resolution of fever, clonus, agitation, and rigidity, and was discharged after five days with psychiatric follow-up. Her antidepressant regimen was changed to low-dose mirtazapine, a non-serotonergic alternative.<br /><br />The report emphasizes the importance of careful medication reconciliation, especially in older adults, who are at higher risk because of polypharmacy and altered drug clearance. Early recognition and prompt treatment are essential for recovery.

Asset Subtitle

Jonathan D. Grube

Meta Tag

Author List Anthony Cervantes, Anvesh Kodali Naga, Dennis Rivera Lopez, Jonathan D. Grube, Kathleen Mattingly, Manoj Gajula, Mitra Chandan, Sai Varun Gadde, Sailesh Mullaguri

Category Clinical Vignettes

Concept Serotonin Syndrome

Concept Hunter Criteria

Concept Altered Mental Status

Concept Autonomic Instability

Concept Neuromuscular Disorder

Distinguished Non-Finalist

Presenter Organization UCF/HCA Ocala Internal Medicine Residency

Presenting Author Jonathan D. Grube

Track Adult

Keywords

serotonin syndrome

venlafaxine

trazodone

Hunter criteria

polypharmacy

serotonergic drugs

clonus

cyproheptadine

elderly patient

medication interaction

Serotonin Syndrome

Hunter Criteria

Altered Mental Status

Autonomic Instability

Neuromuscular Disorder