A 70-Year-Old Woman Presenting with Confusion and Muscle Spasms Due to Serotonin Syndrome Associated with Paroxetine and Quetiapine Treatment

BACKGROUND Serotonin toxicity, often referred to as 'serotonin syndrome,' is a drug-induced condition due to excess serotonin released from brain synapses, resulting in symptoms that may be autonomic, neuromuscular, and/or cognitive in nature. Most cases involve more than 1 of the following drug regimens: monoamine oxidase inhibitors (MAOIs), serotonin releasers, selective serotonin reuptake inhibitors (SSRIs), or serotonin-norepinephrine reuptake inhibitors (SNRIs). This report is of a 70-year-old woman who presented with confusion and muscle spasms due to serotonin toxicity associated with paroxetine and quetiapine treatment. CASE REPORT An elderly woman with dementia presented to the Emergency Department with fever, altered mental status, labile blood pressures, and inducible clonus. No known medication dosage increases had been made, nor had any new serotonergic agents been added to the patient's drug regimen. She underwent a thorough workup in the Emergency Department and later during her hospitalization. A presumptive diagnosis of serotonin toxicity was made early on during her stay, with the etiology attributed to use of paroxetine and quetiapine. Clinical improvement was observed after benzodiazepine administration, discontinuation of offending agents, and a brief cyproheptadine course. The patient survived her hospital stay and was ultimately discharged to hospice care with a return to her baseline level of functioning. CONCLUSIONS Diagnosing serotonin toxicity requires a high degree of clinical suspicion and can occur in the absence of increased dosage of existing, or initiation of new, serotonergic agents.