Viagra is the trade name, generic name of sildenafil citrate tablets, generally used to treat male erectile dysfunction, dapoxetine is generally used to treat and improve male premature ejaculation, the drug should be taken correctly according to the dosage under the guidance of the doctor. 1. Dapoxetine: generally used to treat male premature ejaculation, can play a role in prolonging the duration of sexual life, nausea, diarrhea and other symptoms may occur after taking, allergic to the drug, severe heart failure and other people are prohibited to use. 2. Sildenafil citrate tablets: generally used in the treatment of male erectile dysfunction, can play a role in maintaining erectile hardness and erection time, after taking may appear dizziness, head swelling, blurred vision and other symptoms, low blood pressure, vascular deformity and other people can not take. The drug should be taken under the guidance of a doctor in accordance with the dosage, to avoid unauthorized use, causing damage to the body.