Generic Viagra

As someone who treats men with Viagra nearly every day, I can testify to the remarkable effects of this medication. For many men and their partners, Viagra has unquestionably brought about significant improvements in their lives, and to a degree that was not previously possible with other treatments. And yet there is clearly much more to the story of human sexuality and relationships than the Viagra Myth would have us believe. The Viagra Myth has less to do with the effectiveness of the medication than with our cultural propensity to look for the easy fix. This myth suggests that a pill that improves blood flow to the penis can solve personal relationship issues, no matter how complex. Robert Prensley

At present, 1400kg of highly concentrated pure sidenafil citrate is made each week by an automated process in a factory in Ringsakiddy, Co Cork, Republic of Ireland. Making one batch of the drug takes 21 days. The Scheme below shows the original ‘discovery’ route used to synthesise sildenafil. Commercial manufacture of the drug is by an alternative route, the details of which are strictly under wraps.

The resulting white crystalline powder is taken to one of three centres - in France, Puerto Rico or the US - where it is diluted with inactive ingredients: microcrystalline cellulose, anhydrous dibasic calcium phosphate, croscarmellose sodium, magnesium stearate, hydroxypropyl methylcellulose, titanium dioxide, lactose and triacetin. The powder is then coloured blue, and formulated into the characteristic rounded-diamond-shaped tablets equivalent to 25mg, 50mg and 100mg of sildenafil.

Between 1986 and 1990, hundreds of possible molecules were synthesised and tested in laboratory experiments.

The most promising molecule was given the code name UK-92,480. It showed properties that suggested it would be a good compound to treat angina. Research was redirected to look at this heart disorder.

The medicine was later called Sildenafil and finally renamed Viagra (Sildenafil citrate).