This drug can be taken as needed or in daily basis, but do not take more than 1 tablet every 24 hours. The maximum dose is 20 mg; your doctor may want to start you up with a little less than that, probably around 10 mg, and then take you up from there depending on your physiological response to the medication. Just like the brand name, the effect of the more cheap generic Cialis can have a maximum duration of 30 hours, under proper stimulation. Generic Cialis can be taken with or without food.