Daily Tadalafil Effective for Men Regardless of Testosterone Level
By Reuters Staff
May 29, 2014
NEW YORK (Reuters Health) – Daily tadalafil improves sexual function in men who respond partially to on-demand phosphodiesterase type 5 inhibitor (PDE5I) therapy, regardless of their baseline testosterone levels, a new study from Eli Lilly shows.
However, men with normal testosterone levels had a significantly greater improvement in International Index of Erectile Function (IIEF) Erectile Function domain scores with daily treatment compared to men with low testosterone, Dr. Evan Goldfischer of Premier Medical Group of the Hudson Valley in Poughkeepsie, New York, and colleagues found.
Several studies have shown a lower response to PDE5I treatment in men with low testosterone, Dr. Goldfischer and his team note in their report in Urology, online April 10. And uncontrolled studies have found adding testosterone is more effective than PDE5I monotherapy in men with low levels of the hormone.
“However, additional data are needed to determine if TRT (testosterone replacement therapy) should be considered for all men with low testosterone levels who experience an inadequate response to PDE5I therapy,” they add.
About half of men have a return to normal erectile function with on-demand PDE5I therapy, the researchers note. They previously conducted a randomized trial in partial responders to on-demand PDE51, which found 39% recovered normal erectile function with 5 milligrams a day of tadalafil.
In the current study, the investigators conducted a post-hoc analysis of the treatment response in that study based on testosterone levels. A total of 503 men were included in their analysis, including 167 men on placebo and 336 on tadalafil.
IIEF Erectile Function scores improved significantly with treatment vs. placebo regardless of testosterone levels.
However, men with testosterone levels of 300 ng/ml or higher had a greater improvement in IIEF-EF domain score compared with men with lower testosterone (p=0.022). There were no differences between the low- and normal-testosterone groups in other IIEF domains or in confidence in their ability to maintain an erection.
“Additional studies should assess the impact of testosterone supplementation on response to tadalafil once daily in men with low testosterone levels who did not have adequate responses to optimized PDE5I therapy,” Dr. Goldfischer and colleagues conclude.
Eli Lilly designed and conducted the study and paid for assistance with writing and submitting the report. Dr. Goldfischer and his co-authors reported multiple financial ties to the drugmaker.