orry, you can’t have it back.” Dr Brian Klee, senior medical director at pharmaceutical company Pfizer, had never before encountered such a reaction from patients. Usually, at the end of a failed drug trial, patients were more than happy to give the medication back. Not this time, however, and Klee was confused.
Pfizer had been running trials on a new drug called sildenafil citrate, created by British scientists Peter Dunn and Albert Wood in 1989 (some sources credit Bell, Brown and Terret). They hoped the compound would be useful in treating high blood pressure and angina, a chest pain associated with coronary heart disease. However, the trials were a dismal failure, with the drug showing little effect in treating heart disease. Klee investigated the reason for the patients’ reluctance to part with their medication at the end of the trial. What he discovered was very surprising. “One thing that we found during those trials is that people didn’t want to give the medication back because of the side effect of having erections that were harder, firmer and lasted longer.”
With this unexpected result in mind, Pfizer scientist Ian Osterloh conducted further research to “help us understand how the drug might amplify the effects of sexual stimulation in opening up the blood vessels in the penis. With UK-92480’s chances of treating angina now slim, we decided to run pilot studies on patients with erectile dysfunction.”