Viagra and Heart Diseases – What Does the Science Say in 2017?

It is a well-known fact that Viagra was originally created for treating heart diseases. But something went wrong (in a good sense). It turned out that the drug was more efficient for the treatment of erectile problems. However, independent researchers did not stop investigating the possibility of using this medication for initial purposes. Below we will tell you what the science says about Viagra and heart diseases.

Some Historical Facts

In 1989, chemists of the pharmaceutical company Pfizer synthesized the active substance called UK-92480 in the laboratory of the English city of Sandwich. The main mechanism of action of this substance was that it inhibited the activity of PDE5 enzyme, which led to better vasodilation. At first they thought that the new drug would be useful for the treatment of angina and other heart diseases associated with weakening of blood circulation. In 1991, they secured a patent in which the drug was named sildenafil and had to be used as a heart medication. However, two scientists – Peter Ellis and Nickolas Terret – noted that PDE type 5 inhibitors might be effective in erectile dysfunction.

Indeed, during the second stage of clinical trials (in 1992), it turned out that sildenafil solved erection problems much better, and many participants did not want to give back the pills. Some of them even asked to give them more sildenafil. As a result, scientists began to conduct research in a new direction. The first pilot project for the treatment of erection problems with sildenafil was held in Bristol (England) in 1993.

Between 1994 and 1997, 21 clinical trials involving around 4500 patients with erectile dysfunction were conducted. All these studies showed impressive results. In 1998, the FDA recognized sildenafil as a medicine that made a significant contribution to ED treatment, and in 1998 this US government body approved Viagra as the first oral medicament indicated for the treatment of erection problems.

Interesting fact. Journalists suggest that the name "Viagra" was formed by combining 2 words: Vigor (which means "power" or "energy") and Niagara (the largest waterfall in North America).

The occurrence of Viagra in the pharmaceutical market marked a new era of sexual medicine, giving men of the world firmness and confidence in their abilities.

Old & Recent Findings about Viagra & Heart Diseases

According to the WHO, cardiovascular diseases are the top cause of death worldwide: for no other reason, so many people die each year as from heart and vascular disorders. Therefore, a significant part of clinical studies is devoted to the study of methods of treatment of these diseases.

*Cardiovascular Diseases infographic from heart.org

Scientists returned to the study of Viagra as a possible remedy for the treatment of cardiovascular conditions shortly after the approval of this drug as the first oral drug for ED.

For example, in 2003, Iosa D. discovered that sildenafil at a dosage of 50 mg had the following beneficial effects:

1. improved the results of ECG (electrocardiography) in some individuals;

2. lowered the level of arterial pressure (both systolic & diastolic);

3. improved contractility (systolic function) of the left ventricle of the heart;

4. improved the ability of the heart to fill with blood (diastolic function of the right ventricle).

The scientist summarized that sildenafil could be used to treat persons with cardiovascular diseases, except for severe coronary artery ailment with obstructive changes, hypertrophic subaortic stenosis, and some other serious diseases.

In 2009, Blum A. concluded that the drug improved physical performance and general well-being of men suffering from heart failure with decreased ejection fraction (systolic failure), especially in those who had pulmonary hypertension**. Similar conclusions were drawn in other studies.

Studies of sildenafil for the treatment of heart disease have been conducted up to now. In meta-analysis by Zhuang XD et al. (2013) it was indicated that the use of sildenafil for treatment of heart failure is well-tolerated and does not affect the quality of life. However, not all studies confirm the beneficial effects of sildenafil for heart patients. Study by Wang H. et al. also known as RELAX Trial (2017) showed that sildenafil had no significant effect on clinical status of participants and their exercise capacity; those patients suffered from heart failure with preserved (not decreased) ejection fraction, ie diastolic failure.

Since the results of the studies are contradictory, so far sildenafil has not been officially approved for the treatment of heart disease. Scientists believe that this issue requires further investigation through long-term, randomized research. We can assume that when Viagra generics almost completely fill the market for anti-ED meds, then Pfizer will try to intensify research in the "cardiac direction" and develop new sildenafil-containing medicines for treating heart ailments.

Viagra for Impotence Combined with Heart Diseases

Erectile dysfunction & heart disease affect mainly the same groups of patients. Therefore, it is not surprising that these two diseases often coexist. ED often precedes cardiovascular ailments and is often present in men who suffer from these disorders. In medicine, there is even the following concept: (Jackson G., 2013): a male having ED and no cardiovascular symptoms is a cardiac/vascular patient until a doctor proves otherwise, and a male with known heart or vascular ailment should be checked for his sexual function.

Therefore, it is recommended to consult a doctor before using sildenafil-containing drugs. Perhaps the doctor will identify a developing cardiovascular disease in a patient who needs an anti-ED drug.

According to the official instruction, Viagra should be used with caution in case of the following conditions or cardiovascular diseases:

• uncontrolled high/lowered arterial pressure;
• recent stroke;
• recent heart attack;
• irregular heartbeats & angina;
• heart failure or constriction of the aortic valve;
• heart surgery carried out within the past six months.

Viagra shouldn’t be used in male persons for whom sexual intercourse is inadvisable due to their cardiovascular status. But if a male with heart ailment is able to have sex or exercise without worsening his condition, generally Viagra will be safe for him.

The doctor can prescribe Viagra to a patient if he believes that the use of this drug will be safe in this particular case. If not, the drug may be contraindicated. Probably Viagra will even positively affect the patient's condition (for example, if he suffers from a systolic heart failure). In any case, you should inform your doctor if you have or have had before any cardiovascular disease.

It is important: In combination with nitrates used for treating some heart ailments like angina, sildenafil can cause severe drop in arterial pressure and even fatal hypotension. The medication shouldn’t be used by patients taking nitrates. In addition, nitrates are prohibited to be used by patients who have recently taken sildenafil.

The Bottom Line on Viagra and Heart Ailments

Findings in the use of Viagra for heart disease are promising but at the same time contradictory. Some of them confirm the effect of sildenafil, while others deny it. Therefore, now there is no official position of the manufacturers of Viagra on the use of the drug for the treatment of these diseases. Therefore, you should not self-medicate yourself by using this drug for angina or other heart diseases. If you have ED and have or have had some kind of heart disease, you need to tell the doctor about it so that he or she can advise the correct treatment regimen for you.

References:

**Topic about PH (https://phassociation.org/patients/aboutph/)