Therapeutic single-dose mirtazapine-induced symptomatic bradycardia: A case report

Abstract

Cardiotoxicity is an important adverse effect of some psychotropic drugs. However, cardiac side effects with mirtazapine, which is used for an effective treatment of depression and anxiety, are rare. In this article, a forty-eight-year-old woman referred to psychiatric clinics with depressive symptoms. According to Diagnostic and Statistical Manual of Mental Disorders Fifth Edition (DSM-5) criteria, major depressive disorder was diagnosed and mirtazapine 30mg/day was started. 30 minutes after the first dose of mirtazapine was brought to the emergency room with syncope, nausea, vomiting. She was examined in emergency service. Routine blood tests and ECG was studied. During the examination, the patient was followed up with a heart rate of 33 beats per minute, blood pressure arterial 80/50mmHg and a temperature of 36.1°C. 0.5mg atropine IV and theophylline inhaler were administered and cardiology consultation was requested. After atropine and theophylline administration, the heart rate was 48 beats/min in the second ECG. To the best of our knowledge, it is the first bradycardia developed after mirtazapine use in the literature. Bradycardia has been resolved after the half-life of mirtazapine has passed (37 hours for women). The initial heart rate of our patient was within normal limits prior to mirtazapine administration. There was no reason to explain bradycardia, we think that symptomatic bradycardine is caused by mirtazapine. In conclusion, this case report suggests that mirtazapine may cause bradycardia in patients. Risk factors for bradycardia caused by mirtazapine are unknown. Although in many patients this bradycardine does not cause a clinical outcome, clinicians should be aware of this and should perform ECG monitoring in patients with underlying cardiac disease, especially when prescribing mirtazapine.