If you prefer, you may contact the U. 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. If it is not treated right away, priapism can permanently damage your penis sudden vision loss in one or both eyes. Oral ED medicines might not work or might be dangerous if you also take any of the following: Nitrate medicines. These small differences affect the way each medication works, such as how quickly it takes effect and wears off, and the possible side effects.22 hours ago · Viagra started life as a drug to treat hypertension, or high blood pressure. Missing: amazon. Viagra (sildenafil) is a prescription drug that’s used to treat erectile Missing: amazon. %Viagra mg muy buenas. Revisado en España el 21 de agosto de Son las .