Testosterone undecanoate improves erectile dysfunction in hypogonadal men with the metabolic syndrome refractory to treatment with phosphodiesterase type 5 inhibitors alone

At least 30-35% of men with erectile dysfunction (ED) fail to respond to treatment with phosphodiesterase type 5 (PDE-5) inhibitors. Testosterone (T) has effects not only on sexual desire, but also on the anatomical and physiological substrate of erection. This study analysed the effects of T administration to men unsuccessfully treated for ED with PDE-5 inhibitors only. Twenty-nine men aged 36-75 years (mean 59 years) with ED were studied. They suffered from ED for a mean of 2.7 years and had subnormal plasma T levels (total T <3.5 ng ml(-1) ). They received parenteral testosterone undecanoate for 102 weeks. Changes of the domains of the International Index of Erectile Function (IIEF) were assessed. After 6 weeks of T treatment, the sexual desire domain of IIEF had improved (from 4.1 ± 1.4 to 7.2 ± 1.7) and erectile function as measured by IIEF started to improve, reaching a plateau after 30 weeks (from 9.1 ± 2.1 to 26.5 ± 2.3). Features of the metabolic syndrome also improved. There were no adverse effects of T administration. Addition of T to treatment of hypogonadal men unsuccessfully treated with PDE-5 inhibitors only, appeared useful and acceptably safe.