Avoid eating too much food before using ED medication. It’s important not to get wrapped up in the minutiae here. Read more: Levitra — The other ED drug Although Viagra and Cialis are both practical, Cialis may be preferred for its once-daily dosage, as it gives you more freedom to be spontaneous in your sex life. Viagra: Cialis: Cialis is often referred to as the “weekend pill” because it can provide effects for up to 36 hours. Cialis Side Effects vs Viagra Side Effects When taken as prescribed under the supervision of a healthcare professional, Cialis and Viagra are both safe and effective medications for most men. Because Cialis and Viagra work in similar ways within your body, they usually cause similar side effects.Get sildenafil for as low as $, which is 99% off the average retail price of $ for the most common version, by using a GoodRx coupon. Prices Medicare Drug Info Side . · You can find the most common side effects of Viagra and Cialis below, along with information on the percentage of men who report these side effects at the minimum . blackCAT / Getty Images What Is Cialis? Cialis (tadalafil) is a type of PDE5 inhibitor that the Food and Drug Administration approved in Like other PDE5 .