Friday, June 18, 2010

The Viagra History

The Viagra History
Viagra or Sildenafil citrate was approved to create or enhance erections. The drug was only tested in men who had problems obtaining or maintaining erections, a problem affecting an estimated 30 million American men.

Viagra was born only by chance. In 1991, Dr. Solomon Snyder, a neurobiologist at the Johns Hopkins University School of Medicine, discovered that nitric oxide, a common and short-lived gas, transmits signals between nerve cells.

The gas itself dissipates so fast that the only way to see which nerves might use it was to look for the enzyme at the tip of nerve that produced it.

Snyder found that nerve sells in the brain and those in the penis use the gas. Snyder and his colleagues published an article in Science in 1992 on nitric oxide’s role in the penis.

The authors had stimulated the nerves electrically in the penises of rats and demonstrated erections.

They then blocked the enzyme that produced the gas, and erections in the rats no longer occurred.

In the meantime, Dr. Ian Osterloh in the United Kingdom was directing the development of Viagra, a presumed antianginal drug, for Pfizer. But the drug proved ineffective.

Osterloh noted Snyder article and replaced that some men who had taken Viagra for angina reported erections.

He realized that the drug might be blocking an enzyme that kicks in and makes an erect penis go placid.

The rest is history. Not only did Viagra work for impotence, but it was so effective that the Food and Drug Administration approved it in only 6 months and without consulting an advisory committee of outside system.

In the first five years of its availability on the market, Viagra netted approximately $7.4 billion in total sales for Pfizer Incorporated.

Accurately labeled a blockbuster drug, Viagra was colossally successful from the moment of its release; in its first three months of availability in the United States, $411 million of Viagra was sold, and 2.7 million prescriptions were written for the drug.
The Viagra History
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