Adding testosterone to sildenafil (Viagra) for treatment of erectile dysfunction may not significantly improve the condition, according to American and Swiss researchers.
Sildenafil is commonly prescribed to treat erectile dysfunction, but not all men have success with it. In these cases – and if men have low testosterone – physicians often recommend testosterone replacement therapy in combination with sildenafil, although there is little evidence that this approach is effective.
One hundred forty men between the ages of 40 and 70 participated in the study. All of the men had erectile dysfunction and low testosterone levels. Their ability to have erections was assessed using the erectile function domain of the International Index of Erectile Function (IIEF). Men with IIEF scores of 25 or less were included in the study. For testosterone levels, cutoffs of 11.45 nmol/L for total testosterone and 173.35 pmol/L for free testosterone were established; men with levels below these cutoffs were included.
The study began with all of the men taking sildenafil. Once an effective dose was determined for each participant, the men were divided into two groups. Half of the men received testosterone therapy in the form of a gel they applied to the skin every day. The other half also applied a gel daily, but it was a placebo and contained no testosterone. This treatment lasted for 14 weeks.
After this time, the men’s erectile dysfunction was reassessed. Sildenafil improved the erectile function for all the men. However, the men who had testosterone therapy along with sildenafil did not have significantly better function than men who took sildenafil with the placebo.
The researchers concluded that adding testosterone therapy to sildenafil treatment was “not superior” to using sildenafil with a placebo for treating erectile dysfunction.
These results do not mean that testosterone can’t help men with low testosterone and erectile dysfunction. There were some slight improvements among the participants, but they were not enough to be noteworthy.
“There is no benefit to adding testosterone to [Viagra],” lead researcher Dr. Matthew Spitzer told WebMD. “Treatment is a highly individual situation, and this study does not represent all men. If you benefit from both, you should be comfortable continuing this combined therapy.”
Dr. Spitzer is an endocrinology fellow at Boston University School of Medicine.
The study was published on November 20 in the Annals of Internal Medicine. It did not investigate whether testosterone could improve erectile function without sildenafil.
Annals of Internal Medicine
“Effect of Testosterone on Response to Sildenafil in Men With Erectile Dysfunction”
(Summaries for Patients. November 20, 2012)
Spitzer, Matthew, MD, et al.
“Effect of Testosterone Replacement on Response to Sildenafil Citrate in Men With Erectile Dysfunction: A Parallel, Randomized Trial”
(Abstract. November 20, 2012)
HealthDay via MedlinePlus
“Testosterone Gel Fails to Boost Viagra’s Effects”
(November 19, 2012)
“Hormone No Help for ED Drug Response”
(November 19, 2012)
“Adding Testosterone to Viagra May Not Help ED”