At other pharmacies, prices can range from tens to hundreds of dollars. Numerous sites on the Internet offer Viagra for sale after an “online consultation”, often a simple questionnaire. If it is not treated right away, priapism can permanently damage your penis sudden vision loss in one or both eyes. The patent on Revatio indicated for pulmonary arterial hypertension rather than erectile dysfunction expired in late 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. Priapism, or an erection lasting longer than four hours, is also a potential serious side effect.Sildenafil (Viagra, Revatio) is a moderately priced drug used to treat erection problems in men. It is also used to treat pulmonary arterial hypertension, a serious heart and lung condition. This drug is more popular than comparable drugs. It is available in generic and brand versions. Sildenafil, sold under the brand name Viagra, among others, is a medication used to treat erectile dysfunction and pulmonary arterial hypertension. [4] [8] It is also sometimes used off-label for the treatment of certain symptoms in secondary Raynaud’s phenomenon. [9]. Read on to learn where to buy Viagra and sildenafil online — plus, more about how Viagra works, its alternatives, and how it compares with other ED medications.