Categories: Accidental discoveries , Chemistry in History , Guest posts |  Comments
Guest post by Rowena Fletcher-Wood
It was the 1990s, and drug giant Pfizer was on the trail of an elusive angina medication to relieve constricted blood vessels and lower blood pressure. Pharmaceutical chemists in Sandwich, UK, were focusing their efforts on drugs that release NO (nitric oxide), a highly reactive radical that expands blood vessels and releases physical tension. One promising candidate was sildenafil, which was trialled in Morriston Hospital, Swansea.
It’s always difficult to recruit volunteers for a drug trial: even the best trials in animals, computer simulations and in vitro can’t take into account the full complexity of the human body, it’s strikingly unobvious differences from the rat and the complex interconnectedness of its mechanisms. Unexpected things happen, some of them bad, and some of them beneficial.
Sildenafil, later renamed Viagra for marketing, seemed to be a no-go for angina relief, and the trials were unsuccessful. Pfizer recalled the drug, and an unexpected thing happened: the volunteers resisted. ‘[P]eople didn’t want to give the medication back’, said Pfizer’s Brian Klee, ‘because of the side effect of having erections that were harder, firmer and lasted longer.’ (more…)