Cyclosporine, Ciclosporin (INN), or cyclosporin (former BAN), is an immunosuppressant drug. It is used post-allogenic organ transplant to reduce the activity of the patient's immune system and so the risk of organ rejection. It has been studied in transplants of skin, heart, kidney, lung, pancreas, bone marrow and small intestine. Cyclosporine is a cyclic nonribosomal peptide of 11 amino acids produced by the fungus Hypocladium inflatum gams, initially isolated from a Norwegian soil sample.