Impotence male mainly prescribed type 5 phosphodiesterase inhibitor drugs such as sildenafil, etc., need to be used under the guidance of a professional physician, strictly follow the doctor’s instructions, should not be taken without authorization. Type 5 phosphodiesterase inhibitors mainly include sildenafil, tadalafil, vardenafil and so on. They enhance the effect of nitric oxide (NO) by inhibiting the enzyme phosphodiesterase type 5, which breaks down cyclic guanosine monophosphate (cGMP) in the corpus cavernosum. Nitric oxide (NO) can promote the relaxation of smooth muscle in the corpus cavernosum, blood inflow, thus playing a role in promoting penile erection. The main adverse effects of this class of drugs include headache, flushing, dizziness, nasal congestion, indigestion, and visual abnormalities. It is prohibited for those who are allergic to this class of drugs and its components. It is forbidden to take this type of drug at the same time with nitrate drugs. If you need to use it, you should use it correctly under the guidance of a professional doctor.