Ziru is the brand name and the generic name is Sildenafil Citrate Tablets, which can be effective when used to treat penile erectile dysfunction. Cidi citrate tablets have a highly selective inhibitory effect on phosphodiesterase type 5, which prompts the release of nitric oxide in the corpus cavernosum of the penis by inhibiting the enzyme, further leading to an increase in the level of cyclic guanosine monophosphate, which relaxes the smooth muscle in the corpus cavernosum of the penis, and enables patients to have an erection in response to sexual stimulation by improving the local blood circulation. When the drug is used for the treatment of erectile dysfunction, the effect of the drug can last for about 4 hours, and the therapeutic effect of the drug is directly related to the dose and plasma concentration of the drug, when the dose of the drug is increased, the efficacy of the drug will be significantly enhanced. The main adverse effects of the drug include headache, flushing, and visual abnormalities. Contraindications include patients who are taking nitrate drug therapy, those who are allergic to drug components, etc. Since there are some individual differences in the effectiveness of drug treatment, the specific use of the drug must strictly follow the doctor’s instructions.