Tadalafil is also sometimes taken once a day every day without regard to timing of sexual activity. If you become pregnant while taking tadalafil, call your doctor. It can also interact with many medicines, particularly nitrates used in some types of heart disease and blood pressure medicines. If you need emergency medical care for a heart problem, it will be important for your health care provider to know when you last took Cialis. Take tadalafil at around the same time every day.Taking two 5-milligram (mg) tablets of Cialis is the same as taking one mg tablet. If your doctor prescribes 10 mg of Cialis, you can take two 5-mg tablets to reach this dose. However, it’s important that you only take the dosage of Cialis your doctor prescribes. If they haven’t prescribed 10 mg of Cialis, it’s best not to take two 5. $8 for a daily mg or 5-mg tablet; Generic Cialis (tadalafil) $11 for a single 5-mg oral tablet; $44 for a single or mg oral tablet; Pros & cons free unlimited follow-ups. 1. How it works Cialis is a brand (trade) name for tadalafil which may be used to treat erectile dysfunction (ED) and benign prostatic hyperplasia (BPH). Cialis (tadalafil) works by blocking the action of an enzyme known as cGMP-specific phosphodiesterase type-5 (PDE-5).