Purpose/background: We examined the relative safety and effectiveness of adding a monoamine oxidase inhibitor (MAOI) to a failed tricyclic antidepressant (TCA) trial versus adding a TCA to a failed MAOI trial or adding a TCA to a failed TCA trial in treatment-resistant depression.
Methods/procedures: Data were retrospectively harvested from approximately 2500 treatment charts of subjects with treatment-resistant depression who attended a university mood disorders clinic between 1983 and 2015. Hierarchical linear modeling was used to examine the effectiveness of treatment condition on outcome. Relative adverse event profiles were also examined.
Findings/results: Eighty-four treatment outcome observations were made from 54 subjects who received combination therapy: TCA plus TCA (n = 22), TCA plus MAOI (n = 44), and MAOI plus TCA (n = 18). Treatment condition predicted a poorer (albeit not statistically significant) outcome for TCA plus TCA compared with TCA plus MAOI, or MAOI plus TCA therapy (P = 0.098). Specific adverse events occurred with significantly greater frequency between treatment groups; that is, impotence was more frequent with TCA plus MAOI therapy; headaches and insomnia were more frequent with MAOI plus TCA therapy; and constipation was more frequent with TCA plus TCA therapy. There were no reported or observed hypertensive or serotonergic events.
Implications/conclusions: In contrast to conventional wisdom that combined TCA and MAOI therapy should be avoided, the judicious use of this combination may be relatively safe and effective compared with combined TCA plus TCA therapy. However, sample sizes were limited, and the analysis was nonrandomized and retrospective.