This medication is taken with or without food an hour before sex. Medicines that you take by mouth are called oral medicines. There were some reports of headaches and nausea, however. Side effects Side effects of oral ED medicines are often mild. Tadalafil Cialis. No side effects were reported in sexual partners. These include itraconazole Sporanox, Tolsura , ketoconazole Extina, Ketozole, others and ritonavir Norvir.According to price-comparison site test1.ru, generic Revatio will cost you as little as $ per pill, depending on where you fill your prescription. That’s .  · a light-headed feeling, like you might pass out. Common sildenafil side effects may include: flushing (warmth, redness, or tingly feeling); headache, dizziness; . Treatments for erectile dysfunction are big business, and online scams abound. If you do buy medicines over the internet: Check to see if an online pharmacy .