Sildenafil (compound UK-92, 480) was synthesized a group of pharmaceutical chemists working at Pfizer in Sandwich, Kent, object of study in England.
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was initially studied for hypertension (high blood pressure) and angina pectoris (a symptom of coronary heart disease). The first clinical trials have been conducted in Morriston Hospital in Swansea.
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The first phase of clinical trials under the direction of Ian Osterloh suggested that the drug had little effect on angina, but that it could make marked penile structures. Pfizer decided to market for erectile dysfunction, rather than angina.
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The drug was patented in 1996, is designed for use in erectile dysfunction in the United States food and medicines to 27 March,
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1998, becoming the first oral treatment approved for the treatment of erectile dysfunction in the United States,
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and offered for sale in the United States later this year. It soon became a great success: annual sales Viagra in the period 1999-2001 exceeded $ 1 billion.
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