“...It proved to be of little use for that purpose...”
It might have worked since it opened up more areas the blood could go and thus lowered pressure, somewhere else.
wy69
The premise of Viagra as a blood pressure lowering drug was that it would trigger a release of nitric oxide, which would relax the blood vessels and thereby improve blood flow. As it was, the release of nitric oxide with Viagra is so rapid and substantial that it commonly prompts an erection in males, but the effect on blood pressure and flow are mostly transitory.