The Korean Court system made a ruling against Pfizer in June , allowing for the unhindered domestic production of generic prescription sildenafil. Sildenafil comes as a tablet and suspension liquid to take by mouth. Brand names Why is this medication prescribed? Alpha-blockers are sometimes prescribed for prostate problems or high blood pressure. Sildenafil treats PAH by relaxing the blood vessels in the lungs to allow blood to flow easily. Sildenafil is in a class of medications called phosphodiesterase PDE inhibitors.Dosage. The dose of Cialis you need will depend on whether you’re taking it daily or as needed. Daily doses are often between and 5 milligrams (mg). The as-needed dose is usually 10 mg but can range from 5–20 mg. The typicaldose of Viagra is 50 mg. However, the dosage can range from 25– mg. Sildenafil (Viagra) is used to treat erectile dysfunction (impotence; inability to get or keep an erection) in men. Sildenafil (Liqrev, Revatio) is used to improve the ability to exercise in adults (Liqrev, Revatio) and children 1 year of age and older (Revatio) with pulmonary arterial hypertension (PAH; high blood pressure in the vessels carrying blood to the . Is There Anything Over the Counter That Works Like Viagra? There are several medications and treatments used to treat erectile dysfunction (ED, impotency), including .