CVS – Online Drugstore, Pharmacy, Prescriptions & Health Information. Refill and transfer prescriptions online or find a CVS Pharmacy near you. Shop online, see ExtraCare .Bleeding disorders, history of or Stomach ulcer, or history of or—Chance of problems occurring may be increased. Dosing The dose of this medicine will be different for different patients. Sildenafil treats PAH by relaxing the blood vessels in the lungs to allow blood to flow easily. If you have an erection that lasts more than 4 hours, get medical help right away. Sildenafil is in a class of medications called phosphodiesterase PDE inhibitors. Please expect up to 4 to 6 weeks for reimbursement. Tadalafil Cialis.Sildenafil citrate is a white to off-white crystalline powder with a solubility of mg/mL in water and a molecular weight of VIAGRA is formulated as blue, film-coated rounded-diamond-shaped tablets equivalent to 25 mg, 50 mg and mg of sildenafil for oral administration. 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 . Drug Images What is Viagra? If you have erectile dysfunction (ED), your doctor may recommend that you take Viagra. It’s a prescription drug that’s used in adult .Take sildenafil as needed before sexual activity. It works for up to 36 hours. The most common side effects are headaches, feeling sick, indigestion and dizziness. Similar values for pharmacokinetic parameters were seen in normal volunteers and in the patient population, using a population pharmacokinetic approach. When choosing one, tell your doctor or other health care professional what your preferences are, such as cost, ease of use, how long the drug’s effects last and side effects. If you ever need emergency medical treatment for a heart problem, the healthcare providers who treat you will need to know when you last took sildenafil.