Oral medicine for ED also might not be safe or work well if you have: Very low blood pressure, called hypotension, or uncontrolled high blood pressure, called hypertension. Ask your pharmacist for a list of the ingredients. Most men start with and respond well to the 10 mg tadalafil dose. Erectile dysfunction medications require a prescription from a licensed provider. Tadalafil is sometimes taken as needed, usually at least 30 minutes before sexual activity and not more often than once every 24 hours. Severe liver disease. Psychological factors like stress, depression, or anxiety can also contribute.Tadalafil is the generic name for the brand-name drug Cialis. At the time of publishing, the average cash price of 30, milligram (mg) Cialis tablets is approximately $2,, whereas. How Cialis Works. Tadalafil and other PDE5 inhibitors primarily work by inducing muscle relaxation. Tadalafil stops the breakdown of a chemical responsible for relaxing muscles. In ED and PAH, the drug targets muscle cells in blood vessels. When the blood vessel muscle cells relax, this expands the vessel and increases blood flow; this . How to save on generic Cialis There are many ways to save on Cialis, which is available as both a brand-name and generic medication. Save with GoodRx. GoodRx can help you save over 97% off the average retail price of the generic version. Generic Cialis at certain pharmacies is less than $13 with a free GoodRx discount.