>one clinical trial in the early 1990s, to test whether humans can tolerate a new compound.
All seemed to be going well—except for one weird thing the men enrolled in the study did when nurses went to check on them. “They found a lot of the men were lying on their stomachs,” John LaMattina, who was the head of research and development at Pfizer while this research was ongoing, said on a 2016 episode of the STAT Signal Podcast (listen in around 7:15). ”A very observant nurse reported this, saying the men were embarrassed [because] they were getting erections.” It appeared that the blood vessels dilating were not in the heart, but rather the penis (dilating blood vessels is part of the process that leads to erections).
The sildenafil was working—but in the wrong part of the body. And with that, the so-called “potency pill” was born.