Saturday, July 19, 2014

Viagra + Melanoma = Caution

Viagra + Melanoma = Caution


We fear the skin cancer melanoma for its morbidity. Like most cancers, melanomas may be characterized by their controlled localization and eventual metastasis.
In a group of studies investigating possible mechanisms for melanoma, the results give a convoluted picture.

How could Viagra contribute – or stop – cancer growth?
Ionizing Radiation and Genetic Mutations

Although ionizing radiations are the culprits behind melanomas, the varieties of melanomas are based upon the type of genetic mutations allowable. Possessing DNA that confers the presence of melanin producing cells is the number one reason for melanoma. Skin pigmentation alone does not preclude the likelihood for melanoma.

If the DNA responsible for producing melanin is not present, you will not develop melanoma, although you may develop other forms of cancer.

When considering the effects of ionizing radiation upon the body, not all radiation is equivalent, and other factors need to be considered. Although the most common forms of excessive radiation exposure is the Ultraviolet (from the Sun), there is a significant difference when considering pigmentation, UV-A and UV-B.


UV-A Radiation

Citing UV-A as the first example for damaging radiation, we come away with the following scenario.

UV-A radiation possesses a wavelength of approximately 350 nanometers a wavelength at which the skin will burn and DNA is indirectly photo-oxidized via a free radical mechanism.

UV-B radiation, which will burn the skin, possesses a wavelength of approximately 300 nanometers.

UV-B radiation damages DNA that is responsible for melanoma as well. However, the bio-chemical mechanism is not as clear as for UV-A damaged DNA.

But, transformed DNA is the foundation upon which all melanoma will grow.
Sildenafil (Viagra) and Melanoma

A recent study indicated an increase risk of melanoma in Viagra users. The presence of discriminating health factors alters the virulence of melanoma. Sildenafil (Viagra), for example, alters the biochemical pathways of melanoma in men taking the drug. The reasons for taking sildenafil may be multi-faceted as well—clinical studies have shown that sildenafil is effective in treatment of pulmonary hypertension and angina pectoris. Thus the picture of melanoma becomes cloudier.

Generally, the mechanism by which sildenafil acts is to relax smooth muscle through the increase of blood flow. It’s possible that this accelerates melanoma by increasing blood flow to the cancerous cells. One gives an advantage to the cancer by feeding it.
Melanin, Genes, and Biochemical Signals

The first step in the process occurs when mutations in the genes responsible for melanoma over-produce the substance melanin. Then, over-production of melanin sends a biochemical signal to the areas surrounding the initial site of lesion to advance to non-cancerous regions of skin. Thirdly, biochemical signaling induces healthy skin cells to suppress tumor-inactivating proteins. After that, sildenafil assists in the advance of melanoma by augmenting melanin synthesis. However, vasodilation (increase of blood flow) may have positive aspects.

The use of Viagra and other drugs within the class of vasodilators may be of use in the treatment of leukemia, colorectal cancer and possibly breast cancer. One report by Bing Zhu from the University of Alabama and a group of international workers from the University of Alabama and the German University (in Cairo, Egypt) cite use of sildenafil-class drugs to induce (apoptosis) cell death of colorectal tumors.
Viagra: Cancer Killer or Cancer Promoter?

Although the Viagra class of medicines bear the distinction of being cancer-promoters, cancer-deterrents, and heart drugs, their introduction to the medical community has altered the way in which we view the chemistry in medicine




Side Effects of Viagra: Increased Risk of Melanoma

Viagra is overwhelmingly popular, but some men have experienced side effects. Until this most recent study came out about skin cancer, the most-reported side effects were headaches, vision problems including blindness, and facial flushing.

There is a caution regarding using the drug along with blood pressure medication or nitrates, since that can affect the heart and circulatory system, The notorious ‘prolonged erection,’ providing material for jokes and television shows is possible – but rare. None of these effects have caused usage of Viagra to drop.

That may change, however, based on new data.

The June 2014 issue of Journal of American Medicine (JAMA) reported in a cohort study of almost 29,000 men an increased risk of melanoma seen in men who took Viagra.

There were 142 cases reported of melanoma, a cancer of the skin. Researchers proposed that using sildenafil allowed melanoma to spread. It is important to note that this study did not establish cause and effect. The men’s average age was 65.

Excluding other factors such as sun exposure, where they lived, etc, the risk of melanoma for Viagra users was double that of men who had never used the drug. On the other hand, melanoma statistics have dropped as a whole since 1998.

Dr. Abrar Qureshi, a study author responded to concerns about stopping the use of Viagra by saying men who were inclined toward developing melanoma should speak to their doctors. This research did not indicate that any other forms of skin cancer were affected by the drug.