A four-week study in type 2 diabetics indicated that treatment results in cardiovascular benefits.
ANAHEIM, Calif.—Daily dosing of sildenafil (Viagra) may offer both penile vascular and cardiovascular health benefits in type 2 diabetic men with erectile dysfunction (ED), according to a study at Johns Hopkins School of Medicine in Baltimore.
Diabetic ED is characterized by impaired endothelial function and increased oxidative stress in the penis, so the research team investigated the potential vasculoprotective effects of daily sildenafil treatment. They randomized 300 men (aged 35-70) with documented type 2 diabetes to receive either daily sildenafil (50 mg for one week, then 100 mg for three weeks), or placebo for four weeks.
Analyses were performed at baseline and at four weeks. These included enzyme immunoassays for cyclic guanosine monophosphate (cGMP), an endothelial function marker; 8-isoprostane, an oxidative stress marker; and Bio-Plex suspension array system assays for interleukin-6 and interleukin-8 (inflammatory cytokines).
The researchers, who reported their findings here at the American Urological Association annual meeting, found that serum levels of cGMP increased sixfold in the treatment group, compared with no increase in the placebo group. The serum 8-isoprostane levels declined 23% in the treatment group, while there were no significant changes in the placebo group.
The serum levels of IL-6 and IL-8 trended toward a nonsignificant decrease in the treated men. After four weeks, erectile function improved in the treatment group from 22.8% to 58.2%. No significant changes were observed in the placebo group (27.8% at baseline versus 30.7% at four weeks). Erectile function corrections were done based on answers to the Sexual Health Inventory for Men.
“The suggestion here is that this therapy improves your overall cardiovascular benefits, and in high-risk groups this may be beneficial,” said lead investigator Arthur Burnett, MD, professor of urology at the Brady Urological Institute at Johns Hopkins. By averting cardiovascular complications, he said, it may be possible to save money in the long term, but only future pharmacoeconomic studies can ascertain this.
“I think we need to be looking at the concept that a urologic issue is not in a urologic organ. We are sort of seeing this manifestation [ED] as a systemic effect,” commented Marshall Stoller, MD, professor of urology at the University of California in San Francisco. “It is too early to start prescribing sildenafil on a daily basis because more research is needed.”