The Bothell, Washington-based pharmacologic research company ICOS Corporation was started in 1990, and it began the initial cardiovascular testing of a PDE5 inhibitor called IC351 in 1993. Meanwhile, sildenafil citrate (sildenafil) was discovered to cause improved erectile function as a side effect in a trial testing its efficacy for the treatment of angina pectoris in [...]

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Since the March 27th 1998 FDA approval of the prescription drug Viagra, Pfizer, enjoyed a five plus year monopoly of being the only prescription drug company that could distribute the erectile dysfunction drug Sildenafil Citrate. And as such sold over 1 billion dollars worth of the drug in just the first year of introduction. This [...]

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