FDA Highlights: Viagra appears to be cardioprotective

by Bruce Sylvester – Viagra® (sildenafil citrate) might be useful in safely treating heart disease, researchers reported on Oct. 19, 2014 in l BMC Medicine.  The study suggests that long-term daily use of Viagra could be cardioprotective at different stages of heart disease, with few side effects.

Phosphodiesterase-5 inhibitor (PDE5i), the primary ingredient in Viagra, blocks the enzyme PDE5, which prevents relaxation of smooth muscle tissue. Since PDE5 is present in the heart, prior research was conducted to see of the drug is cardioprotective. But, to date, the cardioprotective effects of PDE5i have remained unclear.

Researchers from the Sapienza University in Rome, Italy conducted a meta-analysis of randomized controlled trials published between January 2004 and May 2014. They evaluated the data for efficacy of PDE5i in providing cardiac protection, and for tolerability and safety.

They identified 24 eligible trials from four research databases: MEDLINE, EMBASE, Cochrane Library and SCOPUS. The trials had enrolled 1622 subjects who were treated with PDE5i or a placebo.

The researchers conducted a parallel analysis of the effect of PDE5i on the size and shape of the heart and its performance.

They found that PDE5i prevented the heart increasing in size and changing shape in subjects diagnosed with left ventricular hypertrophy, which can cause thickening of the muscles in the left ventricle.

They also found that PDE5i improved heart performance in all subjects with any heart condition, and it had no negative effect on blood pressure.

Lead author Andrea Isidori M.D., Ph.D, said, “We found that the main ingredient in Viagra can be used as an effective, safe treatment for several patients with heart disease. Large clinical trials are now urgently needed to build on these encouraging findings.”

The authors concluded that the inhibitor could be used to treat men who suffer from heart muscle thickening and early-stage heart failure. Since most of the studies in the meta-analysis enrolled only men, the researchers called for larger trial on sex-specific long-term treatment responses.