A 64-year-old white male hospital employee developed agitation, diaphoresis, tremors, and nausea while working on a medical floor. He reported taking his morning medications, which consisted of citalopram 60 mg and aripiprazole 5 mg, approximately 1 hour before arriving at work. He had taken his first dose of aripiprazole that morning, whereas the citalopram dose was unchanged for many years. While commuting to work, he experienced worsening somnolence and yawning. His symptoms progressed to lightheadedness, vertigo, and “seeing different colors,” by the time he arrived at work. His medical history included hypertension and coronary artery disease. He denied smoking, alcohol, or illicit drug use. He reported compliance with his antihypertensives and statin medications. In the emergency room, he had large blood pressure fluctuations and complained of nausea and urinary retention. He was somnolent, but oriented and following commands. His pupils were dilated (6 mm) and briskly reactive to light. Motor examination showed diffuse fasciculations, upper-extremity postural tremors, and cogwheel rigidity in the extremities. He had diffuse hyperreflexia, with clonus elicited at both knees and ankles. He had appendicular ataxia and was unable to stand independently. Laboratory and imaging studies, including creatinine phosphokinase, thyroid-stimulating hormone, and urine toxicology and brain MRI and MRA were unremarkable. He was treated with cyproheptadine and admitted for observation and supportive care. Psychiatric medications were held. Within 24 hours, the patient had resolution of all symptoms and clinical findings.