Sildenafil citrate is found in suhagra tablet as a generic brand. Which is used to treat men suffering from the problem of impotence. The effect of this drug lasts for 4 to 6 hours. And if the effect of this medicine lasts for more than 4 hours, seek the help of a doctor immediately. Do not take this medicine with alcohol but drink it with water. Because this can increase the side effects of the drug.