To get the maximum benefit from your medicine, you are advised not to drink large amounts of alcohol before sexual activity. By reporting side effects you can help provide more information on the safety of this medicine. Do not take more than directed 1 tablet a day. It may take some time and trial and error to determine the best dosage as well as the best time to take Cialis. Daily dosing for ED: 2. Maximum effects can be seen between 30 minutes and eight hours.When taken for occasional use to treat ED, the effects of Cialis have been shown to last up to 36 hours. Regardless of the dose prescribed, you should not take . The effect of one tablet lasts for up to 36 hours. The recommended ‘as needed’ dose for Cialis is 10mg, taken prior to anticipated sexual activity. The dose may .  · Cialis (tadalafil) is a phosphodiesterase-5 (PDE-5) inhibitor. It’s used to treat erectile dysfunction (ED) and benign prostatic hyperplasia (BPH). The usual Cialis .