Both Cialis and Viagra work quickly. If you have symptoms of an enlarged prostate gland, such as difficulty peeing or needing to pee urgently, tadalafil works by relaxing the muscles in the prostate and bladder. Emling S. If you need emergency medical care for a heart problem, it will be important for your health care provider to know when you last took Cialis. These PDE5 inhibitors may cause headache, flushing, drop in blood pressure, or other adverse effects. You can take it at least 30 minutes before you want to have sex. Your healthcare provider will discuss which dose is right for you.Vision changes. Muscle pain. But there are some differences. With Viagra, there is a higher risk of vision changes than with Cialis. Among people who take Viagra or sildenafil, 3% get blue vision that lasts a few hours. On the other hand, Cialis has a slightly higher risk of muscle pain than Viagra and vardenafil. Dosage. 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 dose is usually 10 mg but can range from 5–20 mg. The typicaldose of Viagra is 50 mg. However, the dosage can range from 25– mg. Cost: Consultation prices vary based on the prescriber; $5 generic prescriptions Medical Consultation Required: Yes Medications Prescribed: Viagra, Cialis, sildenafil, tadalafil .