Psychological factors like stress, depression, or anxiety can also contribute. Generic vs. How Effective Is Cialis? Stendra avanafil : This is an as-needed medication taken 30 minutes before sex and can last up to six hours. Medical consultations were also taken into consideration, as PDE5 inhibitors require a valid prescription from a licensed medical provider. Brand-name versions of the drug approved for PAH include Adcirca.The normal dosage of Cialis for occasional use in treating ED is 10 mg taken before sexual activity. If you have side effects with the mg dose, your doctor may prescribe a 5-mg dose. If the Cialis (tadalafil) is a popular medication used to treat erectile dysfunction. It’s available in tablets ranging from mg to 20mg. It can cost more than $ for a month’s supply, depending on the dosage you need and the pharmacy you visit. You can save more than 90% on the average retail price at certain pharmacies by using a GoodRx coupon. 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.