Siromus 1 mg Tablet is used for prevention of kidney transplant rejection. Siromus 1 mg Tablet is an immunosuppressant. It works by suppressing your bodyÃÂ¢Ã¢âÂ¬Ã¢âÂ¢s immune response following transplant of an organ (eg. liver, kidney, heart). This helps your body to accept the new organ as if it were your own.