Tadalafil and sildenafil belong to the same class of drugs, there is no which treatment impotence effect. Tadalafil and sildenafil are both selective type 5 phosphodiesterase inhibitors, the same class of drugs clinical efficacy adverse reactions contraindications are similar, so there is no which is better. Tadalafil and sildenafil can both treat erectile dysfunction in men, but they need to be used with sexual stimulation to be effective. The main adverse effects of these drugs are dizziness, headache, increased heart rate, nausea and vomiting. It is prohibited for those who are allergic to the drug, it can not be used while taking nitrate drugs, and patients with heart disease should use it with caution. With sexual dysfunction, it is recommended to go to the hospital for examination first, to clarify the cause of the disease, and use the drug under the guidance of the doctor.