Pfizer scientists initially synthesized sildenafil citrate to treat angina pectoris, a type of chest pain caused by reduced blood flow to the heart. Early research focused on its ability to relax blood vessels, thereby increasing blood flow.
Clinical trials revealed sildenafil did improve blood flow, but not as effectively as hoped for angina. The drug demonstrated a different, unexpected effect: it significantly improved erectile function.
This observation led to a redirection of research. Researchers recognized the potential of sildenafil as a treatment for erectile dysfunction (ED), and subsequent trials confirmed its efficacy in this area.
While initial trials failed to meet expectations for angina treatment, the serendipitous discovery of sildenafil’s effect on ED paved the way for its approval and widespread use as Viagra.
The initial research, although unsuccessful in its primary objective, provided valuable insights into the drug’s mechanism of action and ultimately led to a major breakthrough in the treatment of ED.
