Cialis is also called tadalafil, after taking a few times there is no response, it may not be given to the effective amount of medication, you can be more dosage under the guidance of the doctor, or it may be accompanied by their own primary disease, which leads to the lack of efficacy of the medication, or it may be the drug components have been resistant to the drug ingredients, and insensitive to the components of the drug have been replaced under the guidance of the doctor. Tadalafil is a drug used to treat erectile dysfunction in men, which can inhibit the activity of phosphodiesterase, leading to the relaxation of penile smooth muscle, which can increase the blood flow in the cavernous body of the penis, thus maintaining a very good erection hardness and erection time, and some of the people may experience nausea, vomiting, dizziness and other symptoms after use, which will disappear on their own. The drug should be taken correctly according to the dosage under the guidance of a doctor, and should not be taken for a long time to avoid unnecessary effects on the body.