Cialis is not recommended for people taking any form of nitroglycerin because the combination may lower blood pressure to an unsafe level. Efficacy and safety of tadalafil for the treatment of erectile dysfunction: results of integrated analyses. No, Cialis does not lose potency over time. Generic medications are regulated to work as effectively as their branded counterparts: both Cialis and generic Tadalafil are equally as good at treating ED. A small number of patients taking Cialis also reported abnormal vision.CIALIS for once daily use is a lower dose you take every day. • Do not take CIALIS more than one time each day. • Take one CIALIS tablet every day at about the same time of day. You may attempt sexual activity at any time between doses. • If you miss a dose, you may take it when you remember but do not take more than one dose per day. Cialis is an effective treatment for mild to severe ED. On the standard starting dose of 10mg of the active ingredient in Cialis, tadalafil, 71% of men reported an erection suitable for sex. On a higher 20mg dose of tadalafil, 73% of men reported improved erections. On Cialis Daily, 84% of men reported improved erections and 72% preferred. We have at-home and in-store testing options available ›. Your go-to for Pharmacy, Health & Wellness and Photo products. Refill prescriptions online, order items for delivery or store pickup, and create Photo Gifts.