In some patients, the use of VIAGRA with alpha-blockers can lead to a drop in blood pressure or to fainting medicines called HIV protease inhibitors, such as ritonavir Norvir , indinavir sulfate Crixivan , saquinavir Fortovase or Invirase , or atazanavir sulfate Reyataz some types of oral antifungal medicines, such as ketoconazole Nizoral and itraconazole Sporanox some types of antibiotics, such as clarithromycin Biaxin , telithromycin Ketek , or erythromycin other medicines that treat high blood pressure other medicines or treatments for ED VIAGRA contains sildenafil, which is the same medicine found in another drug called REVATIO. Such patients must not apply any out-of-pocket expenses incurred using this Savings Offer toward any government insurance benefit out-of-pocket spending calculations, such as Medicare Part D true out-of-pocket TrOOP costs You are responsible for reporting use of this Savings Offer to any private insurer, health plan, or other third party who pays for or reimburses any part of the prescription filled using this Savings Offer, as may be required. Please expect up to 4 to 6 weeks for reimbursement. This patent was published in and expired in This is likely to lead to dramatic price reductions. Teva sued to have the latter patent invalidated, but Pfizer prevailed in an August federal district court case.Viagra should be taken at 25 mg per 48 hours in order to be used safely along with this drug, since ritonavir increases the concentration of Viagra. CYP3A4 inhibitors. Viagra should be taken at 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 1 . Erectile dysfunction in older men. Erections mainly involve the blood vessels. And the most common causes of ED in older men are conditions that block blood flow to the penis. These include.