Sildigra is a prescription medication used to treat erectile dysfunction (impotence) in men. Its active ingredient is sildenafil citrate, the same active ingredient found in the brand-name drug Viagra. Sildenafil works by improving blood flow to the penis when a man is sexually stimulated, which helps in achieving and maintaining an erection. It will not cause an erection on its own; sexual arousal is required.Sildigra is a prescription medication used to treat erectile dysfunction (impotence) in men. Its active ingredient is sildenafil citrate, the same active ingredient found in the brand-name drug Viagra. Sildenafil works by improving blood flow to the penis when a man is sexually stimulated, which helps in achieving and maintaining an erection. It will not cause an erection on its own; sexual arousal is required.