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. Remove the syringe from the bottle. If it is not treated right away, priapism can permanently damage your penis sudden vision loss in one or both eyes. Children 1 year of age and older weighing 45 kilograms kg or more—20 mg 3 times a day. Keep from freezing. What special precautions should I follow? During 3 to 6 months of double-blind treatment or longer-term 1 year , open-label studies, few patients withdrew from active treatment for any reason, including lack of effectiveness.Priapism warning: This drug can cause priapism, which is an erection that won’t go away. If you have an erection that lasts more than 4 hours, call or go to the nearest emergency room. If it. 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 . AdOrder ED Meds in Canada. Get treatment for erectile dysfunction by a Canadian doctor. Prescribed online and shipped to you. View treatments and start an online ED visit g Medical Care · Health Canada Approved · 24 Hour Turnaround Time5/5 ( reviews).