Follow-up support: Make sure you can get the help you need if questions or concerns arise after ordering. Take all of the tablets for your daily dose at one time each day; do not divide the tablets to take as separate doses. Your doctor will probably tell you not to take tadalafil if you are taking street drugs containing nitrates. If you are taking tadalafil for erectile dysfunction, your doctor will probably start you on an average dose of tadalafil and increase or decrease your dose depending on your response to the medication. Do not take more or less of it or take it more often than prescribed by your doctor.tadalafil. erectile dysfunction (ED) benign prostatic hyperplasia, or BPH). Tadalafil (Cialis) is available both as brand-name and generic tablets. Common side Missing: online. Cialis (tadalafil): This ED medication works with the same principle as Viagra, but lasts up to 36 hours. It’s available in mg, 5 mg, 10 mg, and 20 mg tablets. . A manufacturer coupon or copay card is not available for Cialis. However, GoodRx discounts are available to help make it more affordable. Tadalafil, the generic version of Cialis is available for about $9 for 30 tablets of the 5 mg strength. See more.