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Assessment of the Efficacy of Combination Therapy with Folic Acid and Tadalafil for the Management of Erectile Dysfunction in Men with Type 2 Diabetes Mellitus


Corresponding Author: Ahmad Asadolahzade, MD, Department of Urology, Urology Research Center, Guilan University of Medical Sciences, Rasht 41448-95655, Iran. Tel: 00981315525259; Fax: 00981315525259; E-mail:



Phosphodiesterase type 5 inhibitors PDE5Is are less effective in diabetic men with erectile dysfunction (ED); however, the effect of combination therapy with folic acid and PDE5Is in these patients has not been investigated.


To evaluate the efficacy and safety of combination therapy with folic acid and tadalafil for the management of ED in men with type 2 diabetes mellitus.


Eighty-three patients with type 2 diabetes mellitus and ED were included in this randomized double-blind clinical trial. They were randomly divided into two groups. Group A was treated with tadalafil 10 mg every other day plus folic acid 5 mg daily and group B received tadalafil 10 mg every other day plus placebo daily for 3 months. The mean International Index of Erectile Function (IIEF) scores before and after treatment in each groups were recorded. Men with diagnosis of psychological ED, spinal cord injury, or who used folic acid in the past 3 months and patients with any contradiction for use of PDE5Is were excluded.

Main Outcomes Measures.

The cross tabulation and independent t-test were used to evaluate the difference between baseline characteristic of the patients in the two groups. Wilcoxon signed-ranks test and Mann–Whitney U-test were used to evaluate the IIEF score and also its changes before and after treatment in the two groups.


The mean IIEF scores before and after treatment were 11.65 ± 2.67 and 16.80 ± 4.03 in group A (P < 0.001) and 12.70 ± 2.31 and 14.37 ± 2.17 in group B (P < 0.001), respectively. The difference of mean IIEF score after treatment between the two groups was significant (16.80 ± 4.03 vs. 14.37 ± 2.17 in groups A and B, respectively) (P = 0.002). Also, the mean IIEF score was significantly increased in group A as compared with group B (5.14 ± 3.84 vs. 1.68 ± 0.99 in groups A and B, respectively) (P < 0.001). Both folic acid and tadalafil were well tolerated by all the patients.


Sexual function in diabetic patients with ED treated with the combination of tadalafil and folic acid improved significantly as compared with the placebo group. The use of folic acid and tadalafil is safe.

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