Cialis is the trade name and generic name for tadalafil tablets, 5mg a day is less harmful when taken as prescribed and may cause adverse reactions such as headaches. The recommended starting dose of tadalafil tablets taken once daily is 2.5mg, which can be increased to 5mg due to individual differences, and is generally less harmful when taken as prescribed. Headache, cough, indigestion and other adverse reactions may occur, usually after stopping the drug can be gradually relieved, so it is generally less harmful. However, it is not recommended to take it every day for special people, such as severe renal insufficiency. When taking this drug, patients who have an erection for more than 4 hours or experience loss of vision in one or both eyes should seek immediate medical attention. This medication should not be combined with nitrates at the same time. The use of this drug is prohibited for people who are allergic to this drug or the components of the formula, unstable angina or have had angina during sexual intercourse, children, women. The drug is prescribed and should be taken in strict compliance with the doctor’s instructions.