Certified Nephrology Nurse Certification (CNN) Practice Exam 2025 - Free Nephrology Nursing Practice Questions and Study Guide

Tacrolimus is recognized as a calcineurin inhibitor because it effectively inhibits the activity of calcineurin, an important phosphatase that plays a critical role in T-cell activation and proliferation. By binding to the immunophilin FK-binding protein, tacrolimus prevents calcineurin from dephosphorylating the nuclear factor of activated T-cells (NFAT), thus inhibiting the transcription of interleukin-2 (IL-2) and other cytokines involved in the immune response.

This mechanism of action is crucial in clinical settings, particularly in organ transplantation, where it helps to prevent graft rejection by suppressing the immune system. Tacrolimus is therefore widely used as an immunosuppressant in transplant recipients.

In contrast, the other substances listed are not calcineurin inhibitors. Penicillin is an antibiotic used to treat bacterial infections, erythromycin is also an antibiotic and works by inhibiting bacterial protein synthesis, and cocaine is a powerful stimulant and local anesthetic with no role in immunosuppression or calcineurin inhibition. Understanding the specific action of tacrolimus and its classification as a calcineurin inhibitor is vital for those in nephrology and transplant nursing, as it directly relates to patient care management in