Cialis and Viagra are equally effective. How should this medicine be used? Both medications are generic now and can be found at discounted rates, making them more accessible to the public than ever before. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. These are commonly prescribed for an enlarged prostate or male pattern baldness. Sildenafil may cause side effects. Which Lasts Longer?Why is this medication prescribed? Sildenafil (Viagra) is used to treat erectile dysfunction (impotence; inability to get or keep an erection) in men. The dose of Cialis you need will depend on whether you’re taking it daily or as needed. Daily doses are often between and 5 milligrams (mg). The as-needed . Drug Images What is Viagra? If you have erectile dysfunction (ED), your doctor may recommend that you take Viagra. It’s a prescription drug that’s used in .