The active ingredient in the Silagra 100mg tablet is sildenafil, which is used to treat erectile dysfunction and impotence. The effect lasts for 4-5 hours so this drug helps men to get a hard longer erection in their sex life. The effect of this medicine lasts for 4-5 hours. You should not eat heavy food and not consume alcohol while taking this medicine, so it is necessary to consult your doctor while taking this medicine.