Sildenafil (Viagra) was developed to treat hypertension and angina. It had little effect, but was found to assist with maintaining erections, so it was further

Sildenafil (Viagra) was developed to treat hypertension and angina. It had little effect, but was found to assist with maintaining erections, so it was further developed for that purpose. Later it was discovered to be effective for pulmonary hypertension and is approved for that use, as well.