Viagra is also known as sildenafil citrate tablets, a small amount of sildenafil citrate tablets is not able to improve the blood supply to the heart and is not recommended for clinical use. Sildenafil citrate tablets have the effect of dilating small arteries, the early stage is used to treat cardiovascular disease, pulmonary hypertension and so on, but later found that it will cause low blood pressure, flushing, visual impairment, the use of the elderly may cause sudden cardiac death, so patients with heart disease is not recommended to use, sildenafil citrate tablets can not treat heart disease, and can not be used as a drug for the treatment of heart disease. Sildenafil citrate tablets can inhibit phosphodiesterase type 5, increase the content of carbon monoxide in the penile corpus cavernosum, make the penis congested and erect, commonly used to treat impotence, should be taken under the formal guidance of a doctor, so as to avoid the occurrence of stroke, high blood pressure, heart disease and so on. Myocardial infarction, arrhythmia patients taking nitroglycerin at the same time, can not take sildenafil citrate tablets. Specifically under the guidance of the doctor according to their own situation, choose the right drug for themselves.