Tadalafil 20mg should not be taken 2 tablets a day. Tadalafil is a commonly used drug for the treatment of erectile dysfunction in men and is a type 5 phosphodiesterase inhibitor. According to the instructions of Tadalafil, its half-life is about 17.5 hours, and the maximum dosage frequency is once a day. 20mg is already its maximum dosage, so you can’t take 2 tablets a day, and overdose will lead to higher levels of the drug in the body, which may increase the probability of adverse reactions. The use of tadalafil may cause adverse reactions such as headache, back pain, and indigestion. Tadalafil is contraindicated in people who are allergic to any of the ingredients in this product, patients who are taking any form of nitrates, guanylate cyclase stimulators, women, children and other people. If you need to use the drug, please use it under the supervision of a specialist physician or pharmacist.