Some medications should not be taken with sildenafil. What special dietary instructions should I follow? Storage Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. What should I do if I forget a dose? This boosts blood flow and helps you get an erection from sexual activity. · You’ll typically take Viagra about 1 hour before sex. You can take the drug 30 minutes to 4 hours before you anticipate sexual activity. Based on how well you respond to this dosage and any side. AdBrowse & discover thousands of brands. Read customer reviews & find best sellers. Free shipping on qualified orders. Free, easy returns on millions of items.1M+ visitors in the past monthPopular Links: Pharmacy · Media · Accessibility · Security. 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 .