The efficacy of Viagra is mainly used to treat problems such as men’s inability to get a normal erection and fast sex life. However, there are many side effects of Viagra: first, long-term use of Viagra can lead to normal erectile dysfunction in men, and even permanent loss of use, because patients rely on the effects of the drug for a long time, its own mechanism of action will gradually fail. Secondly, the use of Viagra can trigger the sudden occurrence of cardiovascular and cerebrovascular diseases in patients, such as acute myocardial infarction, sudden cerebral hemorrhage, sudden death, etc. Thirdly, Viagra can cause vision problems, especially some patients may suffer from glaucoma, and taking Viagra can lead to difficulty seeing clearly, glaucoma recurrence and blindness. Fourth, in addition to the above-mentioned side effects, Viagra can lead to neurological symptoms and gastrointestinal reactions, such as dizziness, headache, nausea, vomiting, etc.