A client who has recently undergone a kidney transplant is prescribed cyclosporine. Which action should the nurse prioritize to prevent potential toxicity?

Post–kidney transplant clients require lifelong immunosuppression to prevent organ rejection. Cyclosporine is commonly used to suppress T-cell activation and reduce the risk of graft rejection. However, it has a narrow therapeutic window and is known for significant nephrotoxicity. Careful monitoring of renal function is essential to detect early signs of toxicity and preserve graft function. Rationale: A. Monitoring BUN and creatinine levels regularly is the priority because cyclosporine is highly nephrotoxic and can cause dose-dependent kidney damage. Rising creatinine and BUN levels may indicate impaired renal perfusion or direct tubular toxicity. Early detection allows for dose adjustment or medication changes to prevent irreversible graft injury. B. Advising the client to consume grapefruit juice is unsafe because grapefruit inhibits cytochrome P450 enzymes, specifically CYP3A4, which metabolizes cyclosporine. This leads to increased drug levels and a higher risk of toxicity, including nephrotoxicity and neurotoxicity. Therefore, grapefruit juice should be strictly avoided rather than encouraged. C. Instructing the client to take cyclosporine with food to reduce gastrointestinal irritation is not the priority intervention for toxicity prevention. While taking the medication consistently with or without food may improve absorption consistency, food intake does not significantly reduce its toxic effects. The primary concern remains monitoring blood levels and renal function. D. Encouraging increased fluid intake does not directly prevent cyclosporine toxicity. Although adequate hydration supports kidney perfusion, it does not counteract the drug’s nephrotoxic effects or prevent accumulation in the body. The most effective strategy is ongoing laboratory monitoring to detect early renal impairment.