Used primarily as an immunosuppressant in organ transplantation to prevent rejection by suppressing T-cell activity. Commonly prescribed in kidney, liver, and heart transplants. Also used in treatment of autoimmune diseases such as severe psoriasis, rheumatoid arthritis, and atopic dermatitis. Available in oral and intravenous forms for systemic use, and as ophthalmic emulsion for dry eye disease. Its targeted action on immune cells makes it valuable in managing immune-mediated conditions with relatively fewer broad immunosuppressive effects compared to other agents.