Interestingly, Cialis has been more linked to improved self-esteem and other psychological factors than the other PDE5 medications. Talk to your doctor about which dosing schedule is right for you. Before taking tadalafil, tell your doctor and pharmacist if you are allergic to tadalafil, any other medications, or any of the ingredients in tadalafil tablets. Tadalafil is its active ingredient and is available as a generic drug. John’s wort. What should I do if I forget a dose? What Is Cialis?Brand-name Cialis: $20 – $80 per dose (5mg, 10mg, 20mg) Generic Cialis (tadalafil): $11 – $44 per dose (5mg, 10mg, 20mg) Daily generic Cialis (tadalafil): $8 per dose (mg, 5mg). Tadalafil is used to treat male sexual function problems (impotence or erectile dysfunction-ED). In combination with sexual stimulation, tadalafil works by increasing blood flow to the penis to. Whichever condition Cialis is used to treat, the recommended maximum dose per day is 20 mg. This is the highest dosage that a doctor may prescribe. Dosage for erectile dysfunction (ED) For.