Complete atrioventricular block associated with concomitant use of metoprolol and paroxetine

A 63-year-old woman, who had been treated with 20 mg of paroxetine and 0.5 mg of alprazolam daily for 1 year and with 50 mg of metoprolol daily for 15 days, presented to a facility elsewhere with presyncope and complete atrioventricular block. Three days after her initial presentation and cessation of metoprolol treatment, she was transferred to our clinic to be considered for permanent pacemaker implantation. Paroxetine treatment was discontinued on day 1 and atrioventricular block resolved on day 5, which was confirmed with a 24-hour Holter recording. No bradyarrhythmia was induced with similar doses of either metoprolol or paroxetine alone. At 2- and 3-year follow-up, the patient was still free of bradyarrhythmia documented with electrocardiography and 24-hour Holter recordings. To our knowledge, we report the first case of complete atrioventricular block associated with coadministration of paroxetine and metoprolol. Increasing physicians' awareness of drug-induced severe bradyarrhythmia might prevent unnecessary implantation of permanent pacemakers.