If you ever need emergency medical treatment for a heart problem, the healthcare providers who treat you will need to know when you last took sildenafil. Ask your healthcare professional how you should dispose of any medicine you do not use. Children younger than 1 year of age—Use and dose must be determined by your doctor. Do not start these medications while taking sildenafil without discussing it with your healthcare provider. Leukemia blood related cancer or Multiple myeloma blood related cancer or Sickle-cell anemia blood disorder —Sildenafil should be used with caution in these patients as problems with prolonged erection of the penis may occur.While Viagra and Cialis captured the market and the audience with their successful treatment of erectile dysfunction symptoms, there are other alternatives to these two . The generic name for Viagra is sildenafil. The drug also has another brand name: Revatio. It works by slowing down the action of PDE5, an enzyme in the blood vessel walls.. This enzyme breaks down. Viagra (sildenafil) is a prescription drug that’s used to treat erectile dysfunction (ED). The drug comes as a tablet you’ll take by swallowing. It’s usually taken as needed about 1 hour.