Do not divide the 40 mg dose. Cialis stays in your system for up to 36 hours and may provide support for erections during that entire time. Follow all directions on your prescription label and read all medication guides or instruction sheets. This condition may require prompt medical treatment to prevent serious and permanent damage to your penis. That means you can have erections whenever you want or need them.Generic versions of Cialis have been available since under the name tadalafil. A long list of companies has been FDA approved to produce tadalafil for treating ED and BPH. Generic Cialis Availability. Last updated on Cialis is a brand name of tadalafil, approved by the FDA in the following formulation(s): CIALIS (tadalafil – tablet;oral) Manufacturer: LILLY Approval date: November 21, Strength(s): 5MG, 10MG, 20MG ; Manufacturer: LILLY Approval date: January 7, The recommended starting dose for Cialis intended for once daily use is mg, take at the same time each day, without regard to timing of sexual activity. This may be increased to 5mg/day based on need and tolerability. May be taken with or without food. Cialis is available as a generic, under the name tadalafil. 3.