Viagra (scientific name: sildenafil citrate) is a medication originally created by Pfizer Pharmaceuticals as a drug to help men who were suffering from hypertension (high blood pressure) and angina pectoris (a form of ischaemic cardiovascular disease) in 1989 in Sandwich, England as compound UK-92,480. In 1991, inventors (also employees at Pfizer’s Sandwich, Kent research facility in England) Andrew Bell, Dr David Brown and Dr Nicholas Terrett discovered that chemical compounds belonging to the pyrazolopyrimidinone class were useful in the treatment of heart problems such as angina pectoris. Dr Nicholas Terrett was named in the 1991 british patent for sildenafil citrate tradenamed Viagra as a heart medicine, and some experts consider him as the father of Viagra. However, sildenafil citrate as a heart medication did not show promise and studies were stopped in 1992.

Pfizer LabsBy 1994, Nicholas Terrett and Peter Ellis discovered during the trial studies of sildenafil as a heart medicine that it also increased inflow of blood into the penis area, allowing men to reverse the lack of ability to get an erection. The drug acts by enhancing the smooth muscle relaxant effects of nitric oxide (NO), a chemical substance that is normally released in response to sexual stimulation. The smooth muscle relaxation allows increased blood flow into the penis leading to an erection when combined with something exciting.

The first phase of clinical trials under the direction of Ian Osterloh suggested that the drug had little effect on angina pectoris, but that it could induce significant penis erections.

Pfizer therefore decided to market it for anti-impotence drug, rather than for heart medication.

Finally, 21 randomized, placebo-controlled clinical trials including more than 3700 patients, ages 19 to 87 years, were held worldwide. The participants had varying degrees of impotence associated with the following:

Some group of patients also had coexisting illnesses, including hypertension and coronary artery disease.

The drug was patented in 1996 and the clinical trials found sildenafil citrate to be so effective, that the US Food and Drug (FDA) approved it for prescription sale only six months after submission (at the end of March, 1998), and without consulting an advisory committee of outside experts because there were no troubling questions and no significant side effects.

Made by Pfizer Pharmaceuticals, Viagra is the first approved non-surgical treatment for male impotence - erectile dysfunction that does not have to be either inserted or injected directly into the penis to achieve and keep an erection.

Viagra soon became a great success: annual sales of Viagra pills in the period 1999–2001 exceeded 1 billion US dollars. Viagra began to be considered as one of the highest money grossing prescription drugs it has ever produced.

Viagra Pills

 

The British Press portrayed Peter Dunn and Albert Wood as the inventors of the process by which the drug was created, a claim which Pfizer disputes. Their names appeared on an application by Pfizer Pharmaceuticals to patent (WOWO9849166A1) the manufacturing process of Viagra (sildenafil citrate). Peter Dunn and Albert Wood are both employees of Pfizer Pharmaceuticals at the Pfizer run research laboratories in Kent and employees are not allowed to discuss their status or non-status as inventors.

Although Viagra is only available by prescription from a doctor, it was advertised directly to consumers on US TV (famously being endorsed by former United States Senator Bob Dole and brazilian soccer star Pelé). Numerous websites on the Internet offer Viagra pills for sale after an “online consultation”, a mere web questionnaire. The “Viagra” name has become so well known that many fake aphrodisiacs now call themselves “herbal Viagra” or are presented as blue tablets imitating the shape and colour of Pfizer’s product. Viagra is also informally known as “the Magic Blue Pill”, “Vitamin V”, as well as many various other nicknames.

In February 2007, it was announced that Boots the Chemist would trial over the counter sales of Viagra in stores in Manchester, England. Men aged between 30 and 65 would be eligible to buy four tablets after a consultation with a pharmacist.

Pfizer’s worldwide patents on sildenafil citrate will expire in 2011–2013. The UK patent held by Pfizer on the use of PDE5 inhibitors as treatment of impotence was invalidated because of obviousness in 2000; this decision was upheld on appeal in 2002.

References:
^ Wikipedia.org Sildenafil Article.
^ Kling Jim. From hypertension to angina to Viagra. Modern Drug Discovery.


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