Antidepressive treatment with monoamine oxidase inhibitors and the occurrence of intraoperative hemodynamic events: a retrospective observational cohort study.

OBJECTIVE To investigate the occurrence of intraoperative hemodynamic events when antidepressive treatment with monoamine oxidase inhibitors (MAOIs) was continued during anesthesia. METHOD A retrospective observational cohort study was conducted among patients who were admitted for elective surgery requiring anesthesia in 8 Dutch hospitals (2004-2010). The index group included current users of irreversible (tranylcypromine) and reversible (moclobemide) MAOIs. The reference group included a sample of nonusers matched to the index group on hospital, type and period of surgery, and type of anesthesia (ratio 1:3). The outcome of interest was the occurrence of the following intraoperative hemodynamic events: hypotension or hypertension and tachycardia or bradycardia. RESULTS Approximately 280,000 surgical procedures were performed in the participating hospitals in the total observational period of 33 years. The index group included 26 and 25 users of tranylcypromine and moclobemide, respectively. The reference groups included 149 nonusers. Intraoperative hypotension occurred less frequently in users of tranylcypromine (46%) than in nonusers (73%) (P = .01). The occurrence of hypertension, bradycardia, and tachycardia during anesthesia was not different between users of tranylcypromine (27%, 50%, and 12%, respectively) and those in the reference group (35%, 61%, and 26%, respectively). The occurrence of hypotension, hypertension, bradycardia, and tachycardia was not different between users of moclobemide and the reference group. CONCLUSIONS Severe adverse hemodynamic events, such as hypertension and tachycardia, did not occur more frequently in users of both the irreversible MAOI tranylcypromine and the reversible MAO-A inhibitor moclobemide compared to nonusers. These findings suggest that there is no longer much justification to discontinue these MAOIs before surgery, with the considerable risk of compromising patients' psychiatric status.