Keygraf 1 Capsule contains Tacrolimus 1mg, an immunosuppressive agent primarily used to prevent organ rejection in patients undergoing allogeneic liver, kidney, or heart transplantation. Tacrolimus acts by inhibiting calcineurin, thereby suppressing T-lymphocyte activation and proliferation, which reduces the immune response against the transplanted organ. This medication is critical in maintaining graft survival and function. Keygraf should be administered under strict medical supervision with dosage individualized based on patient response, organ type, and concomitant immunosuppressive therapy. Monitoring of blood tacrolimus levels is essential to optimize therapeutic efficacy while minimizing toxicity. Common adverse effects include nephrotoxicity, neurotoxicity, hypertension, hyperglycemia, and increased susceptibility to infections. Patients should be advised to report symptoms such as tremors, headache, or signs of infection promptly. Keygraf is contraindicated in patients with known hypersensitivity to tacrolimus or any formulation components. Caution is warranted in patients with hepatic impairment, as metabolism primarily occurs in the liver. Drug interactions are significant, particularly with agents affecting cytochrome P450 enzymes, necessitating careful review of concomitant medications. Regular monitoring of renal function, blood glucose, and blood pressure is recommended during therapy. Keygraf 1 Capsule is a vital component in transplant immunosuppressive regimens to improve graft longevity and patient outcomes.