History of Viagra

Sildenafil (compound UK-92,480) was synthesized by a group of pharmaceutical chemists working at Pfizer's Sandwich, Kent research facility. It was initially studied for use in hypertension (high blood pressure) and angina pectoris (a form of ischaemic cardiovascular disease). Phase I clinical trial`s under the direction of Ian Osterloh suggested that the drug had little effect on angina, but that it could induce marked penile erection`s. Pfizer therefore decided to market it for erectile dysfunction, rather than for angina. The drug was patented in 1996, approved for use in erectile dysfunction by the Food and Drug Administration on March 27, 1998, becoming the first pill approved to treat erectile dysfunction in the United States, and offered for sale in the United States later that year. It soon became a great success: annual sales of Viagra in the period 1999–2001 exceeded billion.

The British press portrayed Peter Dunn and Albert Wood as the inventors of the drug, a claim which Pfizer disputes.Bellis, Mary. the patenting of an aphrodisiac." About.com?. Their names are on the manufacturing patent application drug, but Pfizer claims this is only for convenience.

Even though sildenafil is only available by prescription from a doctor, it was advertised directly to consumers on US TV (famously being endorsed by Bob Dole). Numerous sites on the Internet offer Viagra for sale after an “online consultation”, a mere web questionnaire. The “Viagra” name has become so well known that many fake aphrodisiac`s 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 “Vitamin V”, “the Blue Pill”, as well as various other nicknames.

Pfizer's worldwide patents on sildenafil citrate will expire in 2011–2013. The United Kingdom patent held by Pfizer on the use of inhibitors (see below) as treatment of impotence was invalidated in 2000 because of obviousness; this decision was upheld on appeal in 2002.