The same active ingredient as Cialis at 10% of the cost. Tadalafil is a generic erectile dysfunction medication that s FDA approved and clinically proven to help men with ED get and maintain erections. ivermectin pour on for horses Do not break or split a Cialis tablet. Swallow it whole. For erectile dysfunction, take Cialis just before sexual activity but not more than once per day. It can be used up to 36 hours before sexual activity. Cialis can help achieve an erection when sexual stimulation occurs. An erection will not occur just by taking a pill.