Sildenafil should not be used with any other medicine or device that causes erections. This medicine usually begins to work for erectile dysfunction within 30 minutes after taking it. Check with your doctor right away if you have a sudden decrease in hearing or loss of hearing, which may be accompanied by dizziness and ringing in the ears. For treatment of pulmonary arterial hypertension: For oral dosage forms suspension or tablets : Adults—20 milligrams mg 3 times a day. Although not all of these side effects may occur, if they do occur they may need medical attention.FAQs What to consider Cost Overdose Ask your doctor Q&A Drug Images What is Viagra? If you have erectile dysfunction (ED), your doctor may recommend that you take Viagra. . Ways to save on Viagra. Below, we discuss four ways you can save on Viagra, whether you have insurance or not. 1. Check your insurance coverage. Insurance companies are . Sildenafil citrate is a white to off-white crystalline powder with a solubility of mg/mL in water and a molecular weight of VIAGRA is formulated as blue, film-coated rounded-diamond-shaped tablets equivalent to 25 mg, 50 mg and mg of sildenafil for oral administration.