The Effect of Daily Low Dose Tadalafil on Cerebral Perfusion and Cognition in Patients with Erectile Dysfunction and Mild Cognitive Impairment.

Objective: The aims of this study were to investigate the effects of daily low-dose tadalafil on cognitive function and to examine whether there was a change in cerebral blood flow (CBF) in patients with erectile dysfunction (ED) and mild cognitive impairment. Methods: Male patients aged 50 to 75 years with at least three months of ED (International Index of Erectile Function [IIEF]-5 score <= 21) and mild cognitive impairment (Montreal Cognitive Assessment [MoCA] score <= 22) were included in the study. The subjects were prescribed a low-dose PDE5 inhibitor (tadalafil 5 mg) to be taken once daily for eight weeks. Changes in MoCA score and single-photon emission computed tomography (SPECT) study between the two time-points were assessed by paired t tests. Results: Overall, 30 male patients were assigned to the treatment group in this study and 25 patients completed the eight-week treatment course. Five patients were withdrawn due to adverse events such as myalgia and dizziness. Mean baseline IIEF and MoCA scores were 7.52 +/- 4.84 and 18.92 +/- 1.78. After the eight-week treatment, mean IIEF and MoCA scores were increased to 12.92 +/- 7.27 (p < 0.05) and 21.8 +/- 1.71 (p < 0.05), respectively. Patients showed increased relative regional CBF in the postcentral gyrus, precuneus, and brainstem after tadalafil administration versus at baseline (p < 0.001). Conclusion: The results of this prospective clinical study suggest that daily use of tadalafil 5 mg increases some regional CBF and improves cognitive function in patients with ED and mild cognitive impairment.