Some people may also have ringing in their ears tinnitus or dizziness. Sexual activity may be a strain on your heart, especially if you have heart disease. You are encouraged to report adverse events related to Viatris products by calling U. Both sildenafil and the metabolite have terminal half lives of about 4 hours. A starting oral dose of 25 mg should be considered in those patients [see Dosage and Administration 2. In pulmonary hypertension it works by relaxing blood vessels in the chest.About sildenafil (Viagra) Sildenafil is a medicine used to treat erection problems (erectile dysfunction). Sildenafil is also sometimes used to treat pulmonary hypertension (high blood pressure in the blood vessels that supply the lungs). If you have erection problems sildenafil works by temporarily increasing blood flow to your penis when. This is a generic drug. Even if this drug is covered by Medicare or your insurance, we recommend you compare prices. The MDRx coupon or cash price may be less than . If you’re holding out for a generic version of branded Viagra, you won’t have to wait much longer. Teva Pharmaceuticals plans to release its generic of the “little blue .