Safety of High-intensity Treatment with the Irreversible Monoamine Oxidase Inhibitor Tranylcypromine in Patients with Treatment-resistant Depression

Introduction: Because the irreversible monoamine oxidase inhibitor tranylcypromine (TCP) was introduced nearly 50 years ago, only few studies exist on today's clinical prescribing practice together with 2nd and 3rd generation psychotropic drugs. Methods: We performed a practice-based observational study of patients with depression treated with TCP in two psychiatric departments in Berlin to assess side effects, effectiveness, comedication and acceptance of the low-tyramine diet. Results: We identified thirty-two patients treated with TCP at a mean dose of 51.9 mg/day after an average of 3.3 pre-treatments in the current episode. Dosing of TCP and the use of multiple psychotropic comedications indicate a high-intensity treatment. The most frequent side effects resulted from arterial hypotonia (28%). Dietary restrictions were mainly rated as moderate. 59% of patients remitted (HAMD-(21) < 9 OF CGI-I = 1) and 22% responded (HAMD-21 reduction > 50% or CGI-I = 2). Discussion: A high-intensity treatment of inpatients with TCP is clinically feasible, i.e., the use of high doses and multiple comedications with a good benefit-risk-ratio. Prospective data aiming at comparisons with modern antidepressants and clarifying further safety issues are warranted.