Hypogonadal Men Nonresponders to the PDE5 Inhibitor Tadalafil Benefit from Normalization of Testosterone Levels with a 1% Hydroalcoholic Testosterone Gel in the Treatment of Erectile Dysfunction (TADTEST Study).

Addition of testosterone (T) may improve the action of phosphodiesterase type 5 inhibitors (PDE5-Is) in patients with erectile dysfunction not responding to PDE5-Is with low or low-normal T levels. To confirm this add-on effect of T in men optimally treated with PDE5-Is and to specify the baseline T levels at which such an effect becomes significant. A multicenter, multinational, double-blind, placebo-controlled study of 173 men, 45-80 years, nonresponders to treatment with different PDE5-Is, with baseline total T levels ≤4 ng/mL or bioavailable T ≤ 1 ng/mL. Men were first treated with tadalafil 10 mg once a day (OAD) for 4 weeks; if not successful, they were randomized in a double-blind, placebo-controlled design to receive placebo or a 1% hydroalcoholic T gel (50 mg/5 g gel), to be increased to 10 mg T if results were clinically unsatisfactory. Mean change from baseline in the Erectile Function Domain Score of the International Index of Erectile Function and rate of successful intercourses (Sexual Encounter Profile 3 question). Erectile function progressively improved over a period of at least 12 weeks in both the placebo and T treatment groups. In the overall population with a mean baseline T level of 3.37 ± 1.48 ng/mL, no additional effect of T administration to men optimally treated with PDE5-Is was encountered. The differences between the T and placebo groups were significant for both criteria only in the men with baseline T ≤3 ng/mL. The maximal beneficial effects of OAD dosing with 10 mg tadalafil may occur only after as many as 12 weeks. Furthermore, addition of T to this PDE5-I regimen is beneficial, but only in hypogonadal men with baseline T levels ≤3 ng/mL. [ABSTRACT FROM AUTHOR]