A 68-year-old woman comes to the physician due to nausea and anorexia. Three months ago, she underwent heart transplantation for restrictive cardiomyopathy and she is treated with cyclosporine Her pulse is 76/min and blood pressure is 158/82 mm Hg. There is a well-healed scar on her chest. Serum creatinine is 3.4 mg/dL, and the serum cyclosporine level is markedly increased. A month ago, he had normal blood pressure and normal levels of cyclosporine and serum creatinine
Further questioning reveals that the patient has been drinking increased amounts of grapefruit juice lately as part of an attempt to improve his overall health. Which of the following mechanisms is most likely responsible for this patient's current condition?

Question

A 68-year-old woman comes to the physician due to nausea and anorexia. Three months ago, she underwent heart transplantation for restrictive cardiomyopathy and she is treated with cyclosporine Her pulse is 76/min and blood pressure is 158/82 mm Hg. There is a well-healed scar on her chest. Serum creatinine is 3.4 mg/dL, and the serum cyclosporine level is markedly increased. A month ago, he had normal blood pressure and normal levels of cyclosporine and serum creatinine
Further questioning reveals that the patient has been drinking increased amounts of grapefruit juice lately as part of an attempt to improve his overall health.  Which of the following mechanisms is most likely responsible for this patient's current condition?

Quizplus · Accepted Answer

Eductional Objective: Calcineurin inhibitor nephrotoxicity with resultant impairment of renal function is the most significant adverse effect of cyclosporine.  Cytochrome P450 3A (CYP3A) is responsible for cyclosporine metabolism in the small intestine and liver.  Grapefruit juice inhibits this enzyme and increases the nephrotoxicity of cyclosporine by raising circulating drug levels (pharmacokinetic interaction).
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A 68-Year-Old Woman Comes to the Physician Due to Nausea