Push the plunger of the syringe, then insert the tip into the bottle while holding the bottle upright on a flat surface. This site is intended only for U. If you experience a prolonged or painful erection for 4 hours or more, contact your doctor immediately. Taking sildenafil alone will not cause an erection. Do not drink grapefruit juice if you’re taking sildenafil Revatio for pulmonary hypertension. Alpha-blockers are sometimes prescribed for prostate problems or high blood pressure.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 . Who may not be able to take sildenafil. Sildenafil is not suitable for some people. To make sure it’s safe for you, speak to your doctor or pharmacist before taking sildenafil if you: have ever had an allergic reaction to sildenafil or any other medicine. have recently had a stroke, heart attack or a heart problem – your doctor should. Exclusive Offers · How It Works · Get More InfoService Catalog: Instagram, P.E. Treatments, GET MORE INFO, Terms & Conditions and more.