An open-label, single-arm pilot study to evaluate the efficacy of daily low dose tadalafil on depression in patients with erectile dysfunction.

Background: Many studies have reported not only that depression and antidepressant medications can cause erectile dysfunction (ED), but also that having ED may increase the risk of depression. We investigated the effect of a daily low dose of a phosphodiesterase (PDE) type 5 inhibitor (tadalafil, 5 mg) on depression and levels of brain-derived neurotrophic factor (BDNF) in patients with ED.

Methods: Ten male patients with at least a 3-month history of ED [International Index of Erectile Function (IIEF)-5 score ≤21] and depression [the Korean version of the Patient Health Questionnaire (PHQ)-9 score ≥5] were analyzed in this study. The subjects were prescribed a low dose of a PDE5 inhibitor (tadalafil 5 mg) once daily for 8 weeks. The survey questionnaires were performed using the PHQ-15 and the PHQ-9 before and after administration of 8 weeks of tadalafil. Blood samples used for measuring serum BDNF levels were taken and measured at baseline and after 8 weeks of treatment.

Results: The mean changes in the PHQ-9 and PHQ-15 scores were 3.60±3.27 and 2.00±2.98, respectively. Analyses of the mean changes in the PHQ-9 scores revealed that the depressive symptoms of the subjects were significantly improved after administration of eight weeks of tadalafil (P<0.05). And, there was also a statistically significant increase in the PHQ-15 scores (P<0.05). Serum levels of BDNF were higher after tadalafil treatment compared to before treatment; however, this difference was not statistically significant.

Conclusions: The results of this prospective, clinical study suggest that daily low dose tadalafil may have a potential role in the treatment of depression in patients with ED.