A patient who is prescribed oral cyclosporine should be advised to avoid:

Appeared in: GMCH - 2016

Explanation

Grapefruit juice contains furanocoumarins, which are potent inhibitors of the cytochrome P450 3A4 (CYP3A4) enzyme located in the small intestine and liver.
Cyclosporine is primarily metabolized by the CYP3A4 enzyme.
By inhibiting this enzyme, grapefruit juice decreases the metabolism of cyclosporine, leading to increased absorption and higher, potentially toxic, blood concentrations of the drug.
Elevated cyclosporine levels significantly increase the risk of adverse effects, most notably nephrotoxicity (kidney damage), hypertension, and neurotoxicity.

Option A: Meat does not contain compounds that significantly interact with the CYP3A4 enzyme system or affect the metabolism of cyclosporine.
Option B: Eggs do not have a known interaction with cyclosporine metabolism. They are a source of protein and are generally considered safe for patients on this medication.
Option D: Green leafy vegetables do not interact with cyclosporine. This is a common distractor because they are well-known for their interaction with another medication, warfarin.

Clinical Relevance

Nursing practice connection: Use the key finding related to Food-drug interaction with cyclosporine to guide bedside assessment, documentation, and the next nursing action.
Patient education is a critical nursing responsibility for transplant patients or those with autoimmune diseases who are prescribed cyclosporine. This education must include clear instructions on avoiding grapefruit.
Nurses should teach patients to read labels on juices and other food products, as grapefruit can be a hidden ingredient.
The interaction is not trivial; it can lead to acute kidney injury, severe hypertension, or other life-threatening toxicities. It is a major patient safety issue.

How to Approach the Question

First, identify the key drug in the question stem: 'oral cyclosporine'.
Second, recall the major pharmacological properties of cyclosporine. Recognize it as an immunosuppressant with a narrow therapeutic index and significant drug/food interactions.
Third, specifically access your knowledge about its metabolism. Cyclosporine is famously metabolized by the CYP3A4 enzyme system.
Fourth, evaluate the options based on this knowledge. Scan for foods known to inhibit or induce the CYP450 system.
Fifth, identify 'Grapefruit Juice' as a classic inhibitor of CYP3A4, which would increase cyclosporine levels.
Finally, eliminate the other options. Recognize that 'green leafy vegetables' are a distractor related to warfarin, not cyclosporine, confirming your choice.

Concept Tested & Keywords

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E6 Pharmacology Nursing Lilley 11e Part 3 p. 138-140

E6 Pharmacology KD Tripathi Essentials 9e Part 3 p. 222-224

Practise the full GMCH - 2016

Attempt every question from this paper in a timed mock, then review the full solution for each one.