Erectile dysfunction (ED), or the inability to get an erection, is a complex condition with many possible causes. The cardiovascular system, specifically the thin layer of cells lining the blood vessels called the endothelium, is believed to play a major role in some cases of ED.

As I have written on this blog before, the presence of ED can often be one of the earliest signs of problems in endothelial function that may later progress to heart disease. In such cases of ED, the vascular endothelium loses its capacity to form nitric oxide, which is necessary to dilate the blood vessels in the penis that cause an erection.

If this hypothesis is correct, then a drug designed to treat this damaged vascular endothelium, such as a statin, should help men with ED who do not respond to treatment with Viagra.

One small but promising study involved men who previously failed treatment with Viagra alone. The men were given 80 mg daily of the statin Lipitor or a placebo. Both groups also received 100 mg tablets of Viagra to use for sexual purposes. After 12 weeks, the Viagra-plus-Lipitor group had statistically significant improvement in erectile function, while the placebo group showed no such improvement.

Although the number of men in the study was small, the results nonetheless are promising enough for the authors to call for larger trials to be done.