A natural cyclic polypeptide immunosuppressant isolated from the fungus Beauveria nivea. The exact mechanism of action of cyclosporine is not known but may involve binding to the cellular protein cytophilin, resulting in inhibition of the enzyme calcineurin. This agent appears to specifically and reversibly inhibit immunocompetent lymphocytes in the G0-or G1-phase of the cell cycle. T-lymphocytes are preferentially inhibited with T-helper cells as the primary target. Cyclosporine also inhibits lymphokine production and release. or A drug that is used to treat asthma, allergies, and colds, and to relieve itching caused by certain skin disorders. It has also been used to stimulate appetite and weight gain, and is being studied in the treatment of weight loss caused by cancer and its treatment. Cyproheptadine belongs to the family of drugs called antihistamines.