The little blue pill prescribed today around the world for erectile dysfunction was originally developed in the early 1990s by Pfizer as a treatment for chest pain — and during the early trials, the male volunteers reported a side effect they were extremely reluctant to give up.

The most commercially successful pharmaceutical product of the late 20th century was, in essential respects, invented by a group of middle-aged Welsh men in a former mining town who refused to give back the leftover medication after their chest-pain trial was over. The Welsh trial nurses who collected the unused sildenafil tablets at the end [...] The post The little blue pill prescribed today around the world for erectile dysfunction was originally developed in the early 1990s by Pfizer as a tr