A patient with CAD is prescribed nitroglycerin sublingually.
Which of the following instructions should the nurse provide?

Choice A rationale

Furosemide is a loop diuretic that inhibits the reabsorption of sodium and chloride in the thick ascending limb of the loop of Henle. This action increases the excretion of these ions, as well as potassium, through the kidneys. The increased urinary potassium loss can lead to hypokalemia, a common and potentially dangerous side effect requiring careful monitoring of serum potassium levels (normal range 3.5-5.0 mEq/L).

Choice B rationale

Spironolactone is a potassium-sparing diuretic that acts as a competitive antagonist of aldosterone in the distal convoluted tubule and collecting duct. By blocking aldosterone's effects, it promotes the excretion of sodium and water while promoting the reabsorption of potassium. This mechanism increases serum potassium levels, and therefore, this medication is more likely to cause hyperkalemia, not hypokalemia.

Choice C rationale

Lisinopril is an ACE inhibitor (angiotensin-converting enzyme inhibitor). It blocks the conversion of angiotensin I to angiotensin II, leading to decreased aldosterone secretion. Decreased aldosterone reduces the retention of sodium and water and the excretion of potassium. Therefore, lisinopril is more likely to cause hyperkalemia rather than hypokalemia, making it an unlikely cause.

Choice D rationale

Metoprolol is a beta-blocker that works by blocking the effects of catecholamines on beta-adrenergic receptors. It primarily affects the heart by slowing the heart rate and reducing contractility, thereby lowering blood pressure. It does not directly impact the renal tubules or the handling of potassium, so it is not a direct cause of hypokalemia. Its effect on potassium is considered negligible.

Choice A rationale

While blood pressure is an important vital sign, it is not the primary assessment before administering a hypnotic medication unless the medication has a known and significant effect on blood pressure, such as causing hypotension. Assessing for current or recent blood pressure is not the most crucial factor compared to the patient's history of substance abuse, given the nature of these medications.

Choice B rationale

Recent blood glucose levels are not a primary concern for most hypnotic medications unless the patient has a history of diabetes or the medication is known to affect glucose metabolism. This assessment would be more relevant for medications like corticosteroids or certain antipsychotics, but it is not a routine or critical pre-administration assessment for hypnotics.

Choice C rationale

A patient's dietary intake is generally not the most critical assessment before administering a hypnotic medication, although some foods or beverages, like caffeine, can interfere with sleep. The primary concerns are the patient's history of substance use, other medications, and potential contraindications related to central nervous system depression.

Choice D rationale

Hypnotic medications, which are central nervous system depressants, have a high potential for abuse and dependence. A history of substance abuse, including alcohol or other sedatives, significantly increases the risk of addiction, tolerance, and withdrawal symptoms. Therefore, assessing this history is a crucial step to ensure patient safety and prevent misuse or overdose.