Viagra generally refers to sildenafil citrate, and sildenafil is not recommended for patients with hypertension. According to the post-marketing experience of Sildenafil, Sildenafil medication can lead to serious cardiovascular events, including cerebrovascular hemorrhage, hypertension, hypotension, transient ischemic attack, myocardial infarction, etc. Therefore, the hypertension medication may cause blood pressure disorders, and in serious cases, it may even be life-threatening. Sildenafil is used in the treatment of erectile dysfunction in men by relaxing the walls of blood vessels and increasing blood flow to the penis. The use of the drug can lead to low blood pressure, which is manifested as headache, facial flushing, nasal congestion and vertigo; it can also lead to abnormal erection of the penis, color vision disorders, relaxation of the lower esophageal sphincter, gastric reflux and other adverse reactions. It is contraindicated for people with coronary heart disease and those who are using nitrate drugs. Patients should use the drug under the guidance of a professional physician.