The nurse is administering sodium polystyrene sulfonate to a client in acute kidney injury (AKI). Which laboratory finding indicates that the medication has been effective?

• Glucose [Reference Range: 74 to 106 mg/dL (4.1 to 5.9 mmol/L)]
• Hemoglobin (Hgb) [Reference Range:12-16 g/dL (120-160 g/L)]
• Potassium (K+) [Reference Range: 3.5 to 5.0 mEq/L (3.5 to 5.0 mmol/L)]
• Ammonia [Reference Range: Adult: 10 to 80 Mcg/dL (6 to 47 Mcmol/dL)]

The correct answer is D.

Choice A rationale: While iodine is essential for thyroid hormone synthesis, it is not relevant to the administration of levothyroxine. The client does not need to consume foods high in iodine specifically for taking levothyroxine.

Choice B rationale: While iron supplements can interfere with the absorption of levothyroxine, this statement does not indicate that the client understands when to take levothyroxine correctly.

Choice C rationale: Levothyroxine should be taken in the morning, not at bedtime, to avoid interference with sleep and to optimize absorption.

Choice D rationale: Levothyroxine, a thyroid hormone replacement, should be taken on an empty stomach, preferably in the morning, at least 30 minutes before eating. Taking it on an empty stomach maximizes its absorption and ensures optimal therapeutic effects.

Choice A rationale: Ingestion of Wort can reduce the client's intake of sodium: This information is not directly related to the situation of a renal transplant and graft rejection. It is not the most significant finding regarding the use of St. John's Wort in this context.

Choice B rationale: Adding the herb decreases the need for corticosteroids: There is no evidence or indication that St. John's Wort can decrease the need for corticosteroids, especially in the context of a renal transplant and graft rejection.

Choice C rationale: While St. John's Wort is sometimes used as an herbal remedy for depression, the most significant information, in this case, is its potential to interact with cyclosporine and affect the client's immunosuppressive medication. The focus should be on the drug interaction and the risk it poses to the client's graft health, rather than the reason for using the herb.

Choice D rationale: The most significant information about the finding that the client has been self-administering St. John's Wort is that it can decrease plasma concentrations of cyclosporine. Cyclosporine is an immunosuppressive medication commonly used after a renal transplant to prevent graft rejection. When St. John's Wort is taken concurrently with cyclosporine, it can induce certain liver enzymes responsible for drug metabolism, leading to a decreased concentration of cyclosporine in the bloodstream. This can potentially reduce the effectiveness of cyclosporine in preventing graft rejection, putting the client's transplanted kidney at risk.