A nurse is caring for a client who has been taking lisinopril for several months. The nurse should plan to check which of the following laboratory values to monitor for adverse effects of the medication?

Choice A rationale Lisinopril, an angiotensin-converting enzyme (ACE) inhibitor, primarily impacts the renin-angiotensin-aldosterone system (RAAS) to lower blood pressure. Its primary mechanism of action does not directly or significantly alter serum calcium levels. Calcium regulation is mainly controlled by parathyroid hormone and calcitonin, not the RAAS pathway. Therefore, monitoring calcium is not the primary concern. Normal serum calcium is 8.5-10.2 mg/dL. Choice B rationale Lisinopril acts by inhibiting the conversion of angiotensin I to angiotensin II, leading to decreased aldosterone secretion. Aldosterone promotes sodium and water reabsorption in the kidneys. While lisinopril's action reduces aldosterone, leading to increased sodium excretion, this effect is less pronounced and less of a clinical concern compared to potassium retention. Sodium levels are important but secondary to the risk of hyperkalemia. Normal serum sodium is 135-145 mEq/L. Choice C rationale Lisinopril inhibits the formation of angiotensin II, which in turn reduces the release of aldosterone from the adrenal cortex. Aldosterone's normal function is to promote potassium excretion and sodium retention in the distal tubules of the kidneys. By suppressing aldosterone, lisinopril causes the kidneys to retain potassium, leading to a risk of hyperkalemia. This is a significant and potentially life-threatening adverse effect that requires routine monitoring. Normal serum potassium is 3.5-5.0 mEq/L. Choice D rationale Lisinopril's primary mechanism of action does not have a direct effect on magnesium balance. Magnesium is involved in various enzymatic processes and its homeostasis is primarily regulated by renal excretion and intestinal absorption, influenced by hormones like parathyroid hormone. While magnesium can be affected by diuretic use, it is not a primary concern with ACE inhibitors like lisinopril. Normal serum magnesium is 1.7-2.2 mg/dL.