Viagra is generally referred to as sildenafil, which is only for erectile dysfunction, and dapoxetine for premature ejaculation, both of which differ in adverse effects, indications, and contraindications. Sildenafil is a drug used for the treatment of erectile dysfunction in men, the use of the drug may cause weakness, dizziness, flushing and micro hypotension, nasal congestion and other adverse reactions. And it is prohibited for use in patients who are using or have recently used nitrates and guanylate cyclase stimulant drugs and who are allergic to sildenafil. Dapoxetine is mainly used for the treatment of premature ejaculation, after the use of anxiety, insomnia, dizziness, eye pain, tinnitus, low blood pressure, nausea and vomiting and other adverse reactions, and even serious cardiac arrest. Dapoxetine is contraindicated in people who are allergic to Dapoxetine, have severe pathologic heart disease, have a history of mania or major depression, recent use of monoamine oxidase inhibitors, thioridazine, serotonin re-uptake inhibitors, potent cyp3a4, and people with moderate-to-severe liver damage.