Viagra protects the heart: back to the future for the love pills

New research published today in BMC Medicine shows that Viagra could be used as a safe treatment for heart disease. In this guest post, lead author on the paper, Andrea M. Isidori of Department of Experimental Medicine at Sapienza University of Rome, tells us more about the background to this research and what they found out.

Everybody’s heard of Viagra (sildenafil). It was the first phosphodiesterase type 5 inhibitor (PDE5i) marketed for the treatment of erectile dysfunction. But few people are aware of the other beneficial effects and potential new uses for this class of drugs.

Viagra was originally tested for heart problems – angina pectoris, a chest pain associated with coronary heart disease – on the basis of its vasodilatory effects (in other words it widens the blood vessels). Its results as an anti-angina drug were only modest, but patients reported the unexpected “side effect” of improved erections. The focus of interest in this drug shifted rapidly from the heart to the bedroom.

In the first decade (1998-2008) after its approval, Viagra revolutionized the sex lives of millions and became one of the most commercially successful drugs in the world, with over 1.8 billion pills used by about 35 million people. The number is still growing.

However, the success of the blue pill was accompanied by isolated early reports of cardiovascular events and sudden deaths. Nonetheless, subsequent large surveillance studies merging data from placebo-controlled clinical trials, the prospective observational cohort study and the International Men’s Health Study (IMHS) demonstrated that myocardial infarction and all-cause mortality rates for Viagra were similar to placebo, suggesting that its use was not associated with any greater risk.

So how can we explain the early reports of cardiovascular side effects?

Mainly through its incorrect use alongside nitro compounds (NO-donors). This can produce an acute drop in blood pressure that, combined with the increased oxygen required during sex, can be detrimental in men with heart disease.

Clearly, this is the result of a series of conditions occurring simultaneously. When Viagra is taken correctly, it is no longer a concern. Nevertheless, in the mind of the public, use of the “love pill” was at this time invariably considered dangerous for patients with heart disease.

Now is the time to change public opinion on this type of drug

Today, these drugs can be taken daily to treat other conditions: pulmonary arterial hypertension and lower urinary tract symptoms, for example.

Interest in continuously administered PDE5is is growing in several areas, such as andrology and urology, for rehabilitation of erectile function, relief of the symptoms of benign prostatic hyperplasia and treatment of some bladder disorders; respiratory medicine, for its effects on pulmonary hemodynamics; neurology, to protect the brain against ischemic injury; and rheumatology, for the treatment of Raynaud’s phenomenon.

What about cardiology?

Several animal studies have shown that Viagra attenuates cardiac remodeling, with an anti-hypertrophic and anti-fibrotic effect, and protects the heart against different types of injury.

Some small clinical trials have demonstrated that chronic PDE5 inhibition improves cardiac performance and geometry in various clinical conditions, including heart failure, myocardial infarction and diabetic cardiomyopathy.

https://blogs.biomedcentral.com/on-medicine/2014/10/20/viagra-protects-the-heart-back-to-the-future-for-the-love-pills/