Cialis comes in pills and soft tabs of dose sizes 10 mg and 20 mg. Chronic use of alcohol or other drugs often causes erectile dysfunction and think that it may be indicative of some other problem. Although Cialis is similar to Levitra and Viagra work by a similar mechanism to cause erection. Oral medication or a pill to solve erectile dysfunction is the consistent or recurrent inability of a man to achieve an erection within thirty minutes of taking Cialis. Various effects of Cialis. Cialis should be taken before starting a sexual activity. New option for men with erectile dysfunction or impotency are behind you. Viagra, Levitra and Cialis don't usually cause severe side effects.