Rosano GMC et al. (2005) Chronic treatment with tadalafil improves endothelial function in men with increased cardiovascular risk. Eur Urol 47: 214–222

Endothelial impairment is an etiological factor common to cardiovascular disease and erectile dysfunction (ED). As the oral phosphodiesterase-5 inhibitor sildenafil (Viagra®; Pfizer, Walton-on-the-Hill, UK) has been shown to improve endothelial function in men with ED, Rosano et al. tested the hypothesis that its long-acting counterpart tadalafil (Cialis®; Lilly, Basingstoke, UK) would have a similar effect in men at increased risk of cardiovascular disease.

Thirty-two men with a 10-year cardiovascular risk exceeding 20%, with or without ED, were randomized in a double-blind fashion to either 20 mg tadalafil every second day or to placebo. At the end of the 4-week study period, flow-mediated dilatation (FMD) of the brachial artery had improved significantly to 9.3% in the tadalafil group. No change in FMD was detected in those men that had received placebo. Interestingly, the improvement of FMD in the tadalafil group was maintained for at least 2 weeks after discontinuation of therapy. This sustained increase in FMD was inversely correlated with plasma levels of endothelin-1, a peptide hormone associated with vascular disease. ED status had no effect on outcomes, and only two men receiving the study drug reported adverse events.

The authors have shown that tadalafil has beneficial effects on endothelial function that are maintained following cessation of therapy. Together with the fact that this drug can be used chronically for ED, rather than requiring 'on demand' administration like sildenafil, these new findings make tadalafil worthy of further investigation by both urologists and cardiologists.