Your doctor may adjust your dose if needed. Shake the liquid well for 10 seconds before each use to mix the medication evenly. Although not all of these side effects may occur, if they do occur they may need medical attention. Using this medicine with any of the following may cause an increased risk of certain side effects but may be unavoidable in some cases. Short-Term Pain Medications: If a patient goes into an urgent care clinic with an injury such as a slipped disk or severe back pain, some urgent care clinics will be able to prescribe short-term pain medications.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 . VIAGRA is available by prescription only in 25 mg, 50 mg, and mg tablets. Patients should always ask their doctors for medical advice about adverse events. You are encouraged to report adverse events related to Viatris products by calling (U.S. only). If you prefer, you may contact the U.S. Food and Drug Administration (FDA. The recommended dosage of Viagra for erectile dysfunction (ED) is 50 mg, taken as needed about 1 hour before sexual activity. You can take it 30 minutes to 4 hours before sexual activity. And you.