4.2.6 Diuretics
Diuretics
From Pharmacology for Nurses, OpenStax Chapter 18
Learning Objectives
By the end of this section, you should be able to:
- 18.6.1 Identify the characteristics of the diuretic drugs used to treat hypertension.
- 18.6.2 Explain the indications, actions, adverse reactions, and interactions of the diuretic drugs used to treat hypertension.
- 18.6.3 Describe nursing implications of diuretic drugs used to treat hypertension.
- 18.6.4 Explain the client education related to diuretic drugs used to treat hypertension.
Introduction and Use
Diuretics are a classification of drug that induces sodium loss and increases urine flow. They are typically used to treat hypertension, heart failure, and volume overload states. This chapter will cover diuretics as they are prescribed for hypertension and coronary heart disorders, thiazide and thiazide-like diuretics, and potassium-sparing diuretics. (Loop diuretics, which are also prescribed for heart failure, are discussed in Heart Failure Drugs.)
Link to Learning
FDA Blood Pressure Booklet
The U.S. Food and Drug Administration (FDA) provides a client-oriented webpage listing FDA-approved products currently available to treat hypertension. It provides links to drug classifications such as ACE inhibitors, angiotensin II receptor blockers, beta blockers, calcium channel blockers, and diuretics. A high blood pressure medicines booklet also is available for download.
Thiazide and Thiazide-Like Diuretics
Thiazide and thiazide-like diuretics inhibit the reabsorption of sodium and chloride in the distal renal tubules. These diuretics increase the excretion of sodium and water by the kidneys, producing diuresis in the client, and also create a potassium loss within the body. Along with ACE inhibitors, thiazide and thiazide-like diuretics are often the first line of treatment for clients diagnosed with hypertension and may be used in conjunction with other antihypertensive drugs (Akbari & Khorasani-Zadeh, 2022).
Potassium-Sparing Diuretics
Potassium-sparing diuretics antagonize aldosterone. These drugs reduce aldosterone-induced sodium and water retention in the late distal tubules of the kidneys. These types of diuretics retain potassium within the body; therefore, potassium does not need to be supplemented. Potassium-sparing diuretics are commonly used to treat hypertension and heart failure but should be used cautiously in clients with impaired renal function.
Table 18.11 lists common diuretics and typical routes and dosing for adult clients.
| Drug | Routes and Dosage Ranges |
|---|---|
| Chlorthalidone (Thalitone) |
25–100 mg orally daily; maximum dose 100 mg daily. |
| Hydrochlorothiazide (Microzide) |
12.5–50 mg orally daily. |
| Amiloride (Midamor) |
5–20 mg orally daily; maximum dose 20 mg daily. |
| Spironolactone (Aldactone) |
25–100 mg orally daily |
| Triamterene (Dyrenium) |
Individualized based on client need. When used alone, the starting dose is 100 mg orally twice daily. Maximum dose should not exceed 300 mg orally daily. |
Adverse Effects and Contraindications
Diuretics are used to treat various disorders. Common adverse effects include mineral loss, weakness, fatigue, muscle cramps, palpitations, dizziness, and electrolyte imbalances. Adverse effects from hypokalemia (with thiazide and thiazide-like diuretics) and hyperkalemia (with potassium-sparing diuretics) are potentially severe and/or fatal. Clients with a hypersensitivity to diuretics or their components should not take this classification of drugs. Diuretics should be used cautiously in older clients and clients with hepatic or renal impairment, arrhythmias, or gout.
Table 18.12 is a drug prototype table for diuretics featuring hydrochlorothiazide (a thiazide diuretic). It lists drug class, mechanism of action, adult dosage, indications, therapeutic effects, drug and food interactions, adverse effects, and contraindications.
| Drug Class Thiazide diureticMechanism of Action Inhibits sodium chloride transport in the distal convoluted tubules, thereby causing increased sodium excretion in the kidneys and lowering blood pressure |
Drug Dosage 12.5–50 mg orally daily. |
| Indications To control hypertension To control edemaTherapeutic Effects Lowers blood pressure Decreases edema |
Drug Interactions Dofetilide Antidiabetic drugs Barbiturates Cholestyramine NSAIDs LithiumFood Interactions Alcohol Tobacco |
| Adverse Effects Blurred vision Chills/cold sweats Headache Joint pain/stiffness Nausea/vomiting Sore throat Trembling Weakness Stevens Johnson syndrome |
Contraindications Anuria, hypersensitivityCaution: Orthostatic hypotension Impaired renal function Pregnancy Breastfeeding |
Nursing Implications
The nurse should do the following for clients who are taking diuretics:
- Assess the client’s blood pressure and pulse on an ongoing basis with initial dosing and intermittently during drug therapy.
- Assess the client for electrolyte imbalances and hyperglycemia as well as the client’s urine output. Urine output for an adult should be weight based at 0.5 mL/kg/hour.
- Assess and monitor for adverse effects, drug and food interactions, and contraindications.
- Provide client teaching regarding the drug and when to call the health care provider. See the chart below for client teaching guidelines.
Client Teaching Guidelines
The client taking a diuretic should:
- Take diuretics early in the morning to avoid increased urination during the night and sleep disturbance.
- Take diuretics with food to avoid GI upset, nausea, and vomiting.
- Report a weight loss or weight gain greater than 2 pounds a day or 5 pounds a week to their health care provider.
The client taking a thiazide/thiazide-like diuretic should:
- Report side effects such as low blood pressure, fatigue, bleeding, hypokalemia, weakness, rash, and leg cramps to their health care provider.
- Eat potassium-rich foods such as avocados, bananas, and spinach to replace potassium.
- If diabetic, monitor their blood glucose levels carefully due to these diuretics’ effects on carbohydrate metabolism.
The client taking a potassium-sparing diuretic should:
- Avoid exposure to direct sunlight because spironolactone can cause photosensitivity.
- Avoid potassium-rich foods such as avocados, bananas, beans, and spinach if their potassium levels are high.
Next- 4.2.7 Nitrates
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