Viagra is the trade name, generic name is sildenafil citrate tablets, sildenafil citrate tablets generally do not have the function of time extension, its main role is to treat erectile dysfunction. Patients need to take the drug under the guidance of a doctor. Sildenafil citrate tablets generally do not have time-delaying function, and its main use is to treat erectile dysfunction in men, and it needs to be sexually stimulated after taking it in order to play a therapeutic effect. Time-delaying drugs are mainly drugs for the treatment of premature ejaculation, including 5-hydroxytryptamine reuptake inhibitors such as dapoxetine and paroxetine. Some patients may experience adverse reactions such as headache, flushing, nausea, indigestion, and fatigue during the administration of Sildenafil Citrate, so those who are allergic to the ingredients of Sildenafil Citrate tablets need to be contraindicated. Because sildenafil citrate tablets can enhance the antihypertensive effect of nitrate, patients taking nitrate drugs, do not take this drug, so as not to damage the health of the body. Patients in the use of drugs, if the body abnormal discomfort, need to go to the regular hospital, for relevant examination.