ED medications can cause side effects, and it’s crucial to have access to a medical provider if needed. Payment options: Consider how you’d like to pay. Severe liver disease. They enhance the effects of a chemical the body makes that relaxes muscles in the penis, called nitric oxide. Is 20mg of Cialis better than mg of Viagra? The most common symptoms of erectile dysfunction include difficulty achieving or maintaining an erection and reduced sexual desire.You need a prescription to get Cialis, which you can acquire through your doctor or telehealth sources. Online ordering can be a great alternative if you prefer the . Cialis and Viagra are phosphodiesterase-5 (PDE5) inhibitors used for treating impotence (erectile dysfunction, or ED).; Adcirca is another brand name of tadalafil.; Common side . Pros lasts up to 36 hours for some people, which is longer than Viagra can be taken as needed or on a daily, regular basis daily use allows for a more spontaneous sex life can .