Adding atorvastatin to sildenafil nonresponders helps improve erectile dysfunction

February 23, 2006 Michael O'Riordan

Michael O'RiordanSenior Journalist | michael@theheart.org

Michael O'Riordan joined theheart.org as a medical journalist in 2003, after completing his master's degree in journalism at the University of British Columbia, specializing in health reporting. He is a member of theheart.org team that won the Online News Association Online Journalism Award in the category of Specialty Site Journalism-Independent in 2010.

Michael was born in Toronto, ON and studied at Queen's University in Kingston, ON and the University of Toronto. Prior to joining heartwire, Michael worked for WebMD Canada.

He loves to run and cycle (and occasionally swim). He has completed numerous marathons and is training for a few more, including Boston in 2013. He currently lives in Hamilton, ON.

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From: http://www.theheart.org/article/653843.do

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Philadelphia, PA - Among patients with sexual dysfunction who do not respond to sildenafil (Viagra, Pfizer), adding a high-dose statin to therapy can help improve the response to the impotence medication as well as improve sexual function. According to researchers, the results from this small pilot study suggest that improving vascular endothelial dysfunction can help improve erectile dysfunction (ED) in men who do not initially respond to treatment.

"There is a link between coronary artery disease and erectile dysfunction," lead author Dr Howard Herrmann (University of Pennsylvania, Philadelphia) told heartwire. "Patients with erectile dysfunction are more likely to have coronary disease, and patients with coronary disease and diabetes are more likely to have erectile dysfunction. Part of that connection is the endothelial dysfunction that underlies both atherosclerosis and ED. So they share a number of risk factors. Our theory was that if we could give subjects with endothelial dysfunction a statin we could improve their production of nitric oxide and make Viagra work again."

Published in the March 2006 issue of the Journal of Sexual Medicine, investigators conducting the randomized, double-blind, placebo-controlled trial enrolled 12 men with moderate to severe ED who failed to respond to 100 mg of sildenafil. These nonresponders were randomized to either atorvastatin (Lipitor, Pfizer) 80 mg or placebo and followed for 12 weeks.

Overall, the addition of atorvastatin lowered LDL-cholesterol levels 43%, down from 135 mg/dL at baseline to 78 mg/dL at 12 weeks. Adding atorvastatin also improved scores on the International Index of Erectile Dysfunction (IIEF). The mean IIEF score increased from 10.3 at baseline to 18.0 at 12 weeks, a statistically significant improvement that was apparent as early as week six. There was no significant increase in IIEF domain scores for subjects treated with placebo. Secondary analyses looking at various erectile qualitative measures also showed an improvement with atorvastatin.

According to Herrmann, although investigators did not specifically study mechanisms, improved endothelial function is the presumed reason for the erectile improvement. He noted that statins have been shown to improve endothelial function within hours or days after starting the drugs, well before the reduction of LDL-cholesterol levels.

"We know that the mechanism of an erection involves nitric-oxide production by the endothelium, which then triggers a second messenger, cyclic GMP, which causes relaxation in the arterioles of the penis to allow increased blood flow for an erection," he said. "One of the abnormalities in people with erectile dysfunction is deficient endothelial-cell production of nitric oxide. One of things we know about statins is that they can improve endothelial function and restore some of the capability to make nitric oxide."

In terms of a clinical application, larger clinical trials are needed, said Herrmann. At present, in the absence of hypercholesterolemia and documented coronary artery disease, he said it does not make sense to prescribe a statin to treat ED. ED patients with high cholesterol levels are likely to be taking a statin anyway, he added. Speaking with heartwire, Herrmann said his group had intended to enroll 64 patients, but the arrival of two additional ED medications on the market made patient recruitment difficult. For this reason, he said, the results of the study should be considered hypothesis generating.

The study was supported by an unrestricted medical grant from Pfizer. Herrmann has received honorarium from Pfizer and Lilly ICOS.

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