Plans and Pricing What dosages are available? Read more on male sexual health on the Sexual Health Australia site. You should also ask what results should expect from using the medication. This image may not be used by other entities without the express written consent of wikiHow, Inc. You need a prescription from a doctor to obtain sildenafil.Sildenafil (Viagra). This medicine works best when you take it on an empty stomach an hour before sex. The body takes longer to absorb it after a high-fat meal or alcohol. Its . Sildenafil (Viagra, Revatio) is a moderately priced drug used to treat erection problems in men. It is also used to treat pulmonary arterial hypertension, a serious heart and lung drug is more popular than comparable drugs. It is available in generic and brand versions. Generic sildenafil is covered by most Medicare and insurance plans, but . Viagra is a brand-name prescription drug that’s approved to treat erectile dysfunction (ED).With ED, you’re unable to have or maintain an erection. Viagra is approved for this use in males.