It might work longer if you have mild to moderate erectile dysfunction. Follow-up support: Make sure you can get the help you need if questions or concerns arise after ordering. Some may find that Cialis works in two hours and takes the medicine two hours before sexual activity. Which Lasts Longer? Dosing is as follows: As needed for ED: 5 to 20 mg by mouth as a one-time dose, with a maximum of one dose in 24 hours. Apart from treating ED, Cialis is also prescribed for benign prostatic hyperplasia, a condition characterized by an enlarged prostate.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. 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. Save . Generic Cialis (tadalafil): $11 per 5 mg pill, $44 per 10 mg or 20 mg pill; Generic Cialis Daily (tadalafil): $8 per mg or 5 mg pill; Branded Cialis: $10 per 5 mg pill, $80 per 10 .