Immunosuppressive

Immunosuppressive refers to agents that suppress or reduce the activity of the immune system. They are used to prevent organ transplant rejection and to treat autoimmune diseases by limiting the immune response.

Most immunosuppressants act on lymphocytes or their signaling pathways. Major categories include calcineurin inhibitors such as cyclosporine and tacrolimus; antimetabolites such as azathioprine and mycophenolate mofetil; mTOR inhibitors such as sirolimus and everolimus; corticosteroids such as prednisone; and biologic agents such as rituximab, belatacept, and other pathway-targeted therapies.

Common indications include solid organ transplantation, where they are used to prevent rejection, and autoimmune diseases such as rheumatoid arthritis, systemic lupus erythematosus, inflammatory bowel disease, vasculitis, and certain dermatologic conditions.

Use requires careful monitoring of drug levels for many agents, adjustment to the minimum effective dose, and infection prophylaxis. Vaccination decisions should consider that live vaccines are contraindicated during significant immunosuppression. Drug interactions, particularly with cytochrome P450 enzymes, are common and can affect drug levels and toxicity.

Adverse effects include an increased risk of infections and malignancies, nephrotoxicity (notably with calcineurin inhibitors), hepatotoxicity, hypertension, hyperlipidemia, diabetes, and bone marrow suppression; long-term use may cause metabolic and cosmetic side effects.

See also: organ transplantation, autoimmune disease, transplant pharmacology.