1Contact the transplant team before the next dose, report both CYP3A inhibitors, and anticipate trough and renal monitoring.✓ Correct answer
2Encourage more grapefruit juice because it lowers tacrolimus concentrations through intestinal enzyme induction.
3Continue both products and stop trough monitoring because tremor confirms adequate immunosuppression.
4Add St. John's wort to counteract toxicity without changing tacrolimus or clarithromycin.
Explanation
Tacrolimus is metabolized by CYP3A enzymes. Grapefruit juice and clarithromycin inhibit CYP3A and can markedly raise tacrolimus concentrations, increasing nephrotoxicity and neurotoxicity. The nurse should promptly involve the transplant team before the next dose, report both exposures, and anticipate frequent trough and renal-function monitoring with regimen adjustment. St. John's wort induces CYP3A and can lower tacrolimus exposure enough to cause rejection; it is not a toxicity treatment.
Clinical reasoning The combination of a high trough, tremor, and creatinine rise after new CYP3A inhibitors strongly supports tacrolimus toxicity rather than transplant rejection.
Decision rule Reconcile food, prescription, and herbal interactions whenever tacrolimus levels change; hold independent dosing decisions and obtain transplant-team guidance with close trough and kidney monitoring.
Scenario A kidney transplant recipient taking tacrolimus develops tremor, rising creatinine, and a trough concentration above the prescribed range after starting clarithromycin and drinking grapefruit juice.
Tacrolimus CYP3A interaction — A change in tacrolimus exposure caused by inhibition or induction of CYP3A-mediated metabolism.
Calcineurin-inhibitor nephrotoxicity — Acute or chronic kidney injury associated with tacrolimus exposure, often accompanied by an elevated trough concentration.