Immunosuppressant

Immunosuppressants are medications that dampen or suppress the immune system. They are used primarily to prevent transplant rejection and to treat autoimmune and inflammatory diseases, such as rheumatoid arthritis, systemic lupus erythematosus, inflammatory bowel disease, psoriasis, and certain dermatologic conditions. They also help prevent or treat graft-versus-host disease after hematopoietic stem cell transplantation.

Most immunosuppressants work by interfering with T-cell activation or proliferation, or by reducing immune cell function more broadly. Major drug classes include calcineurin inhibitors (cyclosporine, tacrolimus), mTOR inhibitors (sirolimus, everolimus), antimetabolites (azathioprine, mycophenolate mofetil), corticosteroids (prednisone, methylprednisolone), and alkylating agents (cyclophosphamide). Biological agents such as rituximab, abatacept, and tocilizumab target specific immune pathways.

Treatment requires careful monitoring. Dosing is individualized and often adjusted based on drug levels, blood counts, and organ function. Because they suppress immune defenses, patients are at higher risk of infections and certain cancers, and may experience nephrotoxicity, hepatotoxicity, hypertension, diabetes, lipid abnormalities, osteoporosis or bone loss, and gastrointestinal symptoms. Drug interactions and adherence are important considerations.

Immunosuppressants have dramatically improved transplant survival and outcomes in autoimmune diseases, but they are not curative for most conditions and require long-term management and surveillance.