Viagra is the trade name and Sildenafil Citrate is the generic name. There is no such thing as the best way to take Sildenafil Citrate, which can generally be taken 0.5 to 4 hours before sex. Sildenafil Citrate is a male sexual function improvement drug that is mainly used to treat erectile dysfunction. Its pharmacological effect is that it can stimulate the release of nitric oxide in the corpus cavernosum of the penis, which can make the smooth muscle in the corpus cavernosum relax and blood flow into the corpus cavernosum. The drug does not exist the best time to take this statement, the general patient taking sildenafil citrate can be 0.5 ~ 4 hours before sex, 1 day can be taken up to 1 time, in the absence of sexual stimulation, the drug can not play a therapeutic effect. Some patients may experience adverse reactions such as headache, flushing, dyspepsia, abnormal vision, and nasal congestion while taking this product. If you are allergic to the components of sildenafil citrate, patients taking nitrate are contraindicated to take this drug, so as not to damage your health. The drug should be used under the guidance of a doctor, do not blindly use the drug on your own.