Some antidepressants, such as trazodone or clomipramine, can be administered intravenously in patients with major depressive disorder (MDD), with potential benefits compared to the standard oral treatment, but available data about their efficacy are limited. The present study was aimed to compare the effectiveness of trazodone and clomipramine (intravenous [i.v.] followed by oral administration).

Some 42 patients with a diagnosis of MDD according to the DSM–5 were selected and treated with i.v. trazodone or clomipramine according to clinical judgment. The Hamilton Depression Rating Scale, the Hamilton Anxiety Rating Scale, and the Montgomery-Åsberg Depression Rating Scale were administered at baseline, after 2 weeks, and after 6 weeks, as well as after 1 week of intravenous antidepressant administration. Raters were blinded to type of treatment.

No significant differences were found between treatment groups in terms of effectiveness at endpoint. Borderline statistical significance was found in terms of number of responders in favor of trazodone. In addition, patients treated with trazodone reported fewer total side effects than those treated with clomipramine.

Both i.v. trazodone and clomipramine are rapid and effective options for improving depressive symptoms, although trazodone appears to be tolerated better. Further studies with larger samples and double-blind conditions are warranted to confirm our results.