Grapefruit may interact with tadalafil and lead to unwanted side effects. Get started by completing an online visit. Use the medicine exactly as directed. There may be rare occurrences of priapism or painful, prolonged erections. What important information should you know about Cialis? Cialis can help achieve an erection when sexual stimulation occurs.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.  · The Cialis brand of tadalafil is used in men to treat erectile dysfunction (impotence) and symptoms of benign prostatic hypertrophy (enlarged prostate).. Adcirca and Alyq are used in men and women. 2 days ago · CIALIS once-a-day (5 mg) is for patients who anticipate frequent use of CIALIS (i.e. at least twice weekly). Your doctor can advise on the appropriateness of once-a-day treatment.