Background We undertook a prospective pilot study in a small cohort of patients with renal replacement therapy to determine the cause of erectile dysfunction (ED) and evaluate the role of testosterone replacement therapy and sildenafil.

Methods We investigated 12 patients (eight post-transplant and four on haemodialysis) who presented with ED for hypogonadism and cavernosal insufficiency. We assessed sexual performance before and after treatment by a questionnaire method based on the modified International Index of Erectile Function (IIEF) and National Institutes of Health (NIH) rating. Patients received 250 mg intramuscular monthly injections of testosterone cypionate and 50-100 mg sildenafil orally once or twice weekly for 12 months. Therapeutic response was considered good if the patient could maintain an erection adequate for successful sexual intercourse (NIH criteria) and had a marked improvement in the overall sexual performance (IIEF scoring).

Results Before treatment all patients had severe ED with a poor IIEF score while 11 also had diminished libido. Eleven patients had diminished testicular volume and six had elevated follicle-stimulating hormone levels suggestive of germ cell damage. All patients had a good response to the therapeutic trial of testosterone and sildenafil.

Conclusions Therapy with testosterone and sildenafil may be indicated for those with both cavernosal arterial insufficiency and reproductive hormone abnormalities. Further longer-term data are needed to determine the safety and efficacy of this novel regimen.