Chapter 24: Diuretic therapy and Drugs for Kidney Failure

Why does the location of a diuretics effect on the renal tubules cause a loop diuretic to be more potent than a thiazide or potassium sparing diuretic?

Loop diuretics work on the nephron loop, which results in the greatest loss of sodium and, thus, water. Thiazide and potassium-sparing diuretics work in the distal convoluted tubule after more water reabsorption has occurred.

The patient admitted for heart failure has been receiving hydrochlorothiazide (Microzide). Which laboratory levels should the nurse carefully monitor? (Select all that apply). a. Platelet count b. White blood cell count c. Potassium d. Sodium e. Uric acid

c, d, e; Thiazide diuretics such as hydrochlorothiazide (Microzide) cause loss of sodium and potassium and may cause hyperuricemia. Options a and b are incorrect. Hydrochlorothiazide does not have a direct effect on blood cells.

Which action by the nurse is most important when caring for a patient with chronic kidney disease who has an order for furosemide (Lasix)? a. Assess urine output and renal laboratory values for signs of nephrotoxicity. b. Check the specific gravity of the urine daily. c. Eliminate potassium-rich foods from the diet. d. Encourage the patient to void every four hours.

a; Because the kidneys excrete most drugs, patients with CKD may need a lower dosage of furosemide to prevent further damage to the kidneys. Options b, c, and d are incorrect. Urine specific gravity will not adequately assess renal status, and may be altered by the diuresis secondary to the furosemide. Potassium should be increased when furosemide, a potent loop diuretic, is ordered and not eliminated. If diuresis is occurring, the patient may need to void more often than every four hours.

The nurse is providing teaching to a patient who has been prescribed furosemide (Lasix). Which of the following should the nurse teach the patient? a. Avoid consuming large amounts of kale, cauliflower, and cabbage. b. Rise slowly from a lying or sitting position to standing. c. Count the pulse for one full minute before taking this medication. d. Restrict fluid intake to no more than 1 L per 24-hour period.

b; Loop diuretics such as furosemide (Lasix) may dramatically reduce a patient's circulating blood volume from diuresis and may cause orthostatic hypotension. To minimize the chance for syncope and falls, the patient should be taught to rise slowly from a lying or sitting position to standing. Options a, c, and d are incorrect. Kale, cauliflower, and cabbage contain vitamin K, which does not need to be restricted during diuretic therapy. Monitoring the pulse along with the blood pressure to assess for reflex tachycardia is advised, but the pulse does not need to be taken for one full minute before taking the drug. Fluids should not be restricted during diuretic therapy unless ordered by the provider.

Which of the following clinical manifestations may indicate that the patient metolazone (Zaroxolyn) is experiencing hypokalemia? a. Hypertension b. Polydipsia c. Cardiac dysrhythmias d. Skin rash

c; Metolazone (Zaroxolyn) is a thiazide diuretic and causes potassium loss. Signs of hypokalemia include cardiac dysrhythmias, hypotension, dizziness, and syncope. Options a, b, and d are incorrect. Polydipsia is not associated with hypokalemia. Hypertension is a clinical indication for the use of diuretics. Skin rashes are an adverse effect of metolazone but are not a symptom of hypokalemia.

While planning for a patient's discharge from the hospital, which teaching points would be included for a patient going home with a prescription for chlorothiazide (Diuril)? a. Increase fluid in salt and take to make up for the losses caused by the drug. b. Increase and take a vitamin C, rich foods, such as grapefruit and oranges. c. Report muscle cramping or weakness to the healthcare provider. d. Take the drug at night because it may cause drowsiness.

c; Muscle cramping or weakness may indicate hypokalemia and should be reported to the healthcare provider. Options a, b, and d are incorrect. Patients on diuretic therapy are taught to monitor sodium (salt) and water intake to maintain adequate, but not excessive, amounts. Vitamin C-rich foods do not need to be increased while a patient is taking chlorothiazide. The drug should be taken early in the day to avoid nocturia. It does not cause drowsiness.

A patient with a history of heart failure will be started on spironolactone (Aldactone). Which drug group should not be used, or used with extreme caution in patients taking potassium-sparing diuretics? a. Non-steroidal anti inflammatory drugs b. Corticosteroids c. Loop diuretics d. Angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers

d; ACE inhibitors and ARBs taken concurrently with potassium-sparing diuretics increase the risk of hyperkalemia. Options a, b, and c are incorrect. NSAIDs are used cautiously with all diuretics because they are excreted through the kidney. Corticosteroids and loop diuretics may cause hypokalemia and may be paired with a potassium-sparing diuretic to reduce the risk of hypokalemia developing if a diuretic is needed.