RESUMO
PURPOSE: Even though clinical safety has been established in large studies, ondansetron has been reported to cause adverse cardiovascular events. We present a case of atrial fibrillation in association with ondansetron in the postoperative period. CLINICAL FEATURES: A 47-yr-old, 81 kg female presented with a benign lump in her left breast for lumpectomy. Her past medical history was unremarkable. Physically she was very active, non-smoker and had no allergies. She underwent the procedure under general anesthesia. She received 4 mg of ondansetron intravenously for postoperative nausea and vomiting prophylaxis at the end of the procedure and an additional 4 mg in the recovery room for nausea. Within 15 min after the second dose she was noted to be in atrial fibrillation that required admission to the hospital and procainamide infusion for conversion to normal sinus rhythm. She did not have any evidence of myocardial ischemia, valvular abnormality or pulmonary embolism. CONCLUSION: The 5-hydroxytryptamine 3 receptor (5-HT(3)) antagonist ondansetron has been reported to cause myocardial ischemia, supraventricular and ventricular tachycardia. Postulated mechanism includes inhibition of Bezold-Zarisch cardiac reflex and coronary vasoconstriction. Inhibition of 5-HT(3) receptors in the heart could lead to unopposed action of other serotonin receptors leading to atrial fibrillation or other tachyarrhythmias described in the literature.
