Do not mix the liquid with other medications or add anything to flavor the medication. What special precautions should I follow? Do not start these medications while taking sildenafil without discussing it with your healthcare provider. Sildenafil does not prevent pregnancy or the spread of sexually transmitted diseases such as human immunodeficiency virus HIV. If you are taking sildenafil for PAH, take the missed dose as soon as you remember it. The best time to take sildenafil is about 1 hour before sexual activity, but you can take the medication any time from 4 hours to 30 minutes before sexual activity. · Initial dose: 5 or 20 mg orally three times a day, 4 to 6 hours apart. Maximum dose: 20 mg orally three times a day. Injection: Initial dose: or 10 mg IV bolus three times a day. Comments: No greater efficacy was achieved with oral doses higher than the maximum recommended dose. 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 mg Tablets 4 (Repat Authority Script) – Sildenafil. Private Prescription Price: $ Discounted PBS Price – Concession PBS Price: $ Safety Net Price: $ All prices displayed on this site are in AUD unless otherwise indicated. Actual product or product packaging delivered may vary slightly from product image shown.