Immunosuppressants

Immunosuppressant drugs are used in the prevention of organ transplant rejection. These include cyclosporine, tacrolimus, sirolimus, and basiliximab, all of which operate by curbing lymphocyte growth and replication. The calcineurin inhibitors, cyclosporine and tacrolimus, prevent T-cell activation by blocking IL-2 transcription. They both inhibit calcineurin but via different mechanisms; cyclosporine combines with cyclophilin and tacrolimus binds to the FK506 binding protein. They share side effects such as nephrotoxicity, neurotoxicity, hypertension, hyperlipidemia, hyperuricemia, and diabetes mellitus. However, cyclosporine specifically also treats psoriasis and rheumatoid arthritis, with additional risks of gingival hyperplasia and hirsutism. mTOR inhibitors include sirolimus (also known as rapamycin), which binds to the FKBP, thereby blocking T-cell activation and B-cell differentiation. It's commonly administered to patients post-kidney transplant to prevent rejection, can be synergistically used with cyclosporine, and is also found in drug-eluting stents. Notable side effects include pancytopenia, due to bone marrow tissue suppression, hyperlipidemia, and insulin resistance. Lastly, basiliximab is a monoclonal antibody that obstructs the IL-2 receptor, preventing renal transplant rejection. Its side effects include hypertension, edema, and tremors.