Immunsuppressiv

Immunosuppressive drugs, often called immunosuppressants, are medications that dampen or suppress the body's immune responses. They are commonly used to prevent rejection of transplanted organs and tissues, to treat autoimmune diseases such as rheumatoid arthritis, lupus, and inflammatory bowel disease, and to reduce graft-versus-host disease after bone marrow transplantation.

Mechanisms vary by class. Calcineurin inhibitors (cyclosporine, tacrolimus) inhibit T-cell activation by blocking calcineurin signaling. Sirolimus and everolimus are mTOR inhibitors that limit T- and B-cell proliferation. Antimetabolites such as azathioprine, mycophenolate mofetil, and methotrexate interfere with purine synthesis or DNA replication. Corticosteroids (prednisone, prednisolone) exert broad anti-inflammatory effects. Biologic agents (rituximab, abatacept, belimumab) target specific immune pathways.

In clinical practice, immunosuppressants are often used in combination to balance efficacy with toxicity. Dosing is individualized and frequently monitored by drug trough levels (especially calcineurin inhibitors). Common adverse effects include increased infection risk, nephrotoxicity (notably with CNIs), hypertension, hyperlipidemia, diabetes, liver injury, bone marrow suppression, and increased cancer risk. Drug interactions via cytochrome P450 enzymes are common and require careful management.

Therapy is typically long-term and may be life-long in transplant patients; stopping abruptly can precipitate rejection. Vaccination and infection prophylaxis are important considerations. The choice of agents depends on the indication, organ involved, comorbidities, and prior therapies, with ongoing monitoring for efficacy and adverse effects.