Serotonin syndrome induced by Bromfed DM in a patient on sertraline

Serotonin syndrome (SS) is a potentially life-threatening condition caused by excessive serotonergic activity in the central nervous system. It is commonly linked to combinations of serotonergic prescription drugs; however, over-the-counter or prescription cold medications containing dextromethorphan (DM) or first-generation antihistamines may also pose a risk. We report a case of a 52-year-old male on sertraline who developed SS after taking Bromfed DM, a cough syrup containing brompheniramine, pseudoephedrine, and DM. Three days after starting the medication, he experienced confusion, dilated pupils, myoclonic foot movements, and difficulty with speech. Symptoms improved following the discontinuation of both sertraline and Bromfed DM. This case underscores the importance of recognizing the serotonergic potential of common cold medications and the risk of SS even at therapeutic doses, particularly in patients on selective serotonin reuptake inhibitors (SSRIs). Prompt identification and cessation of the causative agents are critical to avoid complications.