It’s available in 50 mg, mg, and mg tablets. The most common symptoms of erectile dysfunction include difficulty achieving or maintaining an erection and reduced sexual desire. It affects the way the medicine works. Summary Cialis and Viagra are both pills for treating erectile dysfunction. Other warning signs of an unsafe online pharmacy include outdated medication, no customer service, or suspiciously low prices.Cialis comes in several different strengths, including: milligrams (mg) 5 mg. 10 mg. 20 mg. The cost for these different strengths depends on whether you have insurance, your individual plan. About tadalafil Brand names: Cialis, Adcirca. About tadalafil. Tadalafil is a medicine used to treat erection problems (erectile dysfunction) and symptoms of an enlarged prostate (benign prostate enlargement). It’s also sometimes used to treat pulmonary hypertension (high blood pressure in the blood vessels that supply the lungs). 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.