Correlation of Tacrolimus Blood Levels with Graft Function in Renal Transplant Patient

Abstract

The purpose of this research was to correlate TACROLIMUS blood levels with graft function and to maintain Tacrolimus blood levels within the therapeutic range in renal transplant patients. Objective: To prevent and minimize the risk of graft dysfunction and assessment of drug levels and its correlation to graft function. Methodology: In the department of nephrology at KIMS Hospital, a retrospective study was conducted on sixty patients who are on Tacrolimus and have received a kidney transplant. The study was conducted for a period of six months. Results: Suitable statistical tools were used and data was analyzed which revealed that the patients with graft dysfunction have higher mean serum creatinine and Tacrolimus levels. Conclusion: Our study concludes that graft function correlates with tacrolimus trough levels. When tacrolimus blood levels exceed those in the desired range, creatinine levels rise, resulting in delayed and dysfunctional grafts. Tacrolimus trough levels should be maintained to achieve good graft function. Even a slighter change in the systemic exposure to a drug is clinically significant. Therefore, frequent therapeutic drug monitoring and individualized drug dosage regimens are recommended.

Introduction

Overview:
Kidney transplantation involves surgically placing a healthy donor kidney into a recipient with end-stage renal failure (ESRF). It improves survival and quality of life and is preferred over dialysis due to its cost-effectiveness and long-term benefits.

1. Kidney Anatomy & Function:

• The kidneys are retroperitoneal organs vital for homeostasis, filtering toxins, regulating blood pressure, producing hormones (e.g., erythropoietin), and maintaining acid-base and fluid balance.

• Each kidney contains about 1.2 million nephrons, the functional units responsible for filtration.

• Blood flows to the kidneys via the renal artery, and glomerular filtration rate (GFR) is ~125 mL/min (180 L/day).

2. History of Transplantation:

• First successful human kidney transplant occurred in 1954 between identical twins (Dr. Joseph Murray).

• Progress evolved from animal trials to live and deceased donor transplants.

• Immunosuppression began in the 1960s, enabling unrelated donor transplants.

3. Types of Kidney Transplant:

• Living Donor: Genetically related or unrelated.

• Deceased Donor: From brain-dead or circulatory-dead donors.

• Living donor transplants have better outcomes and lower costs.

4. Indications for Transplant:

• ESRF (GFR <15 mL/min).

• Causes: diabetes, hypertension, glomerular diseases, recurrent kidney stones, congenital defects, etc.

• Transplant indicated in severe electrolyte imbalances, fluid overload, malnutrition, and symptomatic uremia.

5. Contraindications:

• Absolute: Active infection, cancer, severe heart/lung disease, active drug use.

• Relative: Obesity, frailty, poor compliance, limited life expectancy.

6. Evaluation Process:

• Includes medical, surgical, and immunologic assessments (HLA typing, crossmatch).

• Cardiovascular screening is critical due to high post-transplant cardiac risk.

• Screening for cancer, infections, and coagulopathies is also done.

7. Transplant Procedure:

• Involves surgery for both donor and recipient.

• Kidney is implanted in the recipient’s iliac fossa, connecting vessels and ureter.

• Can be done via open or minimally invasive laparoscopic/robotic techniques.

8. Organ Preservation:

• Kidneys are preserved using cold ischemia techniques with solutions like the University of Wisconsin solution.

• Warm ischemia is avoided due to higher risk of injury.

• Pulsatile machine perfusion is a newer technique to improve organ viability.

9. Complications:

Renal Complications:

• Acute/chronic rejection

• Acute tubular necrosis, thrombosis, infections, and ureteral obstructions

Extra-Renal Complications:

• Amyloidosis, malignancies, osteonecrosis, joint calcification

Infection Risks:

• Due to immunosuppressants, including opportunistic and nosocomial infections.

Kidney transplantation remains the most successful and frequently performed organ transplant, offering significant clinical and economic advantages, though it requires thorough patient selection, surgical expertise, and post-operative care to manage potential complications.

Conclusion

Our study concludes that graft function correlates with tacrolimus trough levels. In our study, a total of 60 renal transplant subjects were included. 41had good graft function, 6 had slow graft function, 6had delayed graft function, and 7 had graft dysfunction.When tacrolimus blood levels exceed those in the desired range, creatinine levels rise, resulting in delayed and dysfunctional grafts.Tacrolimus trough levels should be maintained to achieve good graft function. Even a slighter change in the systemic exposure to a drug is clinically significant. Therefore,frequent therapeutic drug monitoring and individualized drug dosage regimens are recommended.

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Copyright

Copyright © 2025 Mrs. P. Twila Pushpa, Dr. E. Ravi, M. Akshitha Reddy, K. Gagandeep, N. Manoj, S. Dhania. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.