Cyclosporines are calcineurin inhibitors belonging to the immunosuppressant agent class of drugs. It is a metabolite extracted from the Tolypocladium fungus. Cyclosporine is a potent immunosuppressive agent that prolongs existence of allogeneic transplants in the lungs, small intestines, pancreas, heart, skin, liver, kidneys, and bone marrow. Cyclosporine suppresses certain cell-mediated immune reactions such as allograft rejection, encephalomyelitis, Freund’s adjuvant arthritis, graft diseases, experimental allergy, and delayed hypersensitivity for a variety of organs and certain humoral immunity. Cyclosporine is sometimes prescribed for patients with autoimmune myasthenia gravis in order to treat dry eye.