Mirtazapine-Induced Premature Ventricular and Atrial Contractions

Mirtazapine, an alpha-2 adrenergic receptor, 5-hydroxytryptamine (5-HT)2, and 5-HT3 antagonist, is commonly used in patients for depression and anorexia. Its mechanism disinhibits serotonin and norepinephrine. Though typically a well-tolerated medication, a rare adverse effect is arrhythmia, including ventricular bigeminy. To date, no case report has cited normal dosing of mirtazapine as a cause of premature ventricular or premature atrial contractions. Only cases of mirtazapine overdose have been associated with arrhythmias, including QT prolongation and bradycardia. We report on a unique case of a 64-year-old female who developed sinus tachycardia with premature ventricular and atrial contractions after starting mirtazapine.