19.5: Diuretics

Learning Objectives

By the end of this section, you should be able to:

• 19.5.1 Identify the characteristics of the diuretic drugs used to treat heart failure.
• 19.5.2 Explain the indications, actions, adverse reactions, and interactions of the diuretic drugs used to treat heart failure.
• 19.5.3 Describe nursing implications of diuretic drugs used to treat heart failure.
• 19.5.4 Explain the client education plan related to diuretic drugs used to treat heart failure.

Diuretics were introduced in Antihypertensive and Antianginal Drugs. This chapter discusses diuretics that are used in heart failure, specifically loop diuretics and thiazide and thiazide-like diuretics. Typically, potassium-sparing diuretics, except for mineralocorticoid receptor agonists, are used sparingly in the treatment of heart failure because the combination of ACE inhibitor or ARB with a potassium-sparing diuretic can lead to increased potassium levels.

Loop Diuretics

Loop diuretics block the reabsorption of sodium and chloride in the loop of Henle, which is located in the renal tubule. Due to the way the sodium pump works, loop diuretics also block the reabsorption of potassium. Loop diuretics in general are more potent than thiazide diuretics since the majority of sodium and chloride reabsorption occurs in the loop of Henle. Loop diuretics are often the first choice of diuretics in treating heart failure.

Clinical Tip

Potassium Supplements

Clients should be informed they may have to take prescribed potassium supplements when taking loop diuretics.

Safety Alert

Diuretics

Loop diuretics are potent diuretics that can lead to profound dehydration and electrolyte loss.

Thiazide and Thiazide-Like Diuretics

As discussed in Antihypertensive and Antianginal Drugs, thiazide and thiazide-like diuretics block the reabsorption of sodium and chloride in the distal renal tubule. Due to the nature of sodium reabsorption, thiazide and thiazide-like diuretics cause potassium loss as well as sodium loss.

Table 19.14 lists common loop diuretics and thiazide/thiazide-like diuretics used in heart failure and typical routes and dosing for adult clients.

Table 19.14 Drug Emphasis Table: Diuretics Used in Heart Failure (source: https://dailymed.nlm.nih.gov/dailymed/)

Drug	Routes and Dosage Ranges
Bumetanide (Bumex)	Heart failure: Oral: 0.5–2 mg twice daily; maximum dose: 10 mg daily. Intramuscular/intravenous (IV): 0.5–1 mg every 2–3 hours; maximum dose: 10 mg daily.
Furosemide (Lasix)	Edema: 20–80 mg orally twice daily; maximum dose: 600 mg daily. (Doses exceeding 80 mg daily must be monitored carefully with frequent follow-up and laboratory monitoring.)
Torsemide (Demadex)	Heart failure: 10–20 mg orally daily, titrated; maximum dose: 200 mg daily.
Chlorothiazide (Diuril)	Edema: 250–500 mg IV once or twice daily; maximum dose: 1000 mg daily.
Chlorthalidone (Thalitone)	Edema: 50–100 mg orally daily or 100 mg every other day; maximum dose: 200 mg daily.
Hydrochlorothiazide (Microzide, HCTZ)	Edema: 25–100 mg orally daily.
Indapamide (Lozol)	Edema: 2.5 mg orally daily; maximum dose: 5 mg daily.
Metolazone (Zaroxolyn)	Edema or heart failure: 5–20 mg orally once daily.

Adverse Effects and Contraindications

Adverse effects include severe anaphylactic/anaphylactoid reaction, excessive loss of water and electrolytes, ototoxicity, tinnitus and hearing loss, vertigo, dizziness, aplastic anemia, thrombocytopenia, agranulocytosis, hemolytic anemia, leukopenia, anemia, Stevens-Johnson syndrome, drug rash, and cramping/diarrhea.

Clients with hypersensitivity to diuretics should not take this classification of drugs. All diuretics should be used with caution in older clients and/or clients with hepatic or renal impairment, arrhythmias, or gout.

Table 19.15 is a drug prototype table for diuretics featuring furosemide (a loop diuretic). It lists drug class, mechanism of action, adult dosage, indications, therapeutic effects, drug and food interactions, adverse effects, and contraindications. (Hydrochlorothiazide, a thiazide/thiazide-like diuretic, was featured in Antihypertensive and Antianginal Drugs.)

Table 19.15 Drug Prototype Table: Furosemide (source: https://dailymed.nlm.nih.gov/dailymed/)

Drug Class Loop diuretic Mechanism of Action Blocks the reabsorption of sodium in the loop of Henle, which causes sodium and water to be excreted	Drug Dosage Edema: 20–80 mg orally twice daily; maximum dose: 600 mg daily. (Doses exceeding 80 mg daily must be monitored carefully with frequent follow-up and laboratory monitoring.)
Indications Hypertension Congestion and/or edema in heart failure Therapeutic Effects Lowers blood pressure Decreases edema	Drug Interactions Aminoglycoside (may increase risk of ototoxicity) Food Interactions No significant interactions
Adverse Effects Severe anaphylactic/anaphylactoid reaction Orthostatic hypotension Excessive loss of water and electrolytes Ototoxicity Tinnitus and hearing loss Vertigo Dizziness Aplastic anemia Thrombocytopenia Agranulocytosis Hemolytic anemia Leukopenia Anemia Stevens-Johnson syndrome Drug rash Cramping/diarrhea	Contraindications Allergy to furosemide Anuria Caution: Hepatic disease Renal disease

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 should be at least 30 mL/hour or 600 mL/24 hours.
• 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 below for client teaching guidelines.

Client Teaching Guidelines

The client taking any type of diuretic should:

• Take diuretic as prescribed by the health care provider.
• Take diuretic earlier in the day (morning) so that diuresis occurs before sleeping times.
• Report a weight loss or weight gain greater than 2 pounds a day or 5 pounds a week to the health care provider.
• Notify their health care provider about symptoms such as dizziness, lightheadedness, or fainting because these could be related to low blood pressure.

The client taking a loop diuretic should:

• Report adverse effects such as dizziness or lightheadedness, fatigue, increased bleeding, tinnitus, weakness, and leg cramps to the provider.
• Eat potassium-rich foods to replace potassium.

FDA Black Box Warning

Diuretics

Loop diuretics are a potent diuretic and could lead to diuresis with water and electrolyte depletion.

Case Study

Read the following clinical scenario to answer the questions that follow.

Anna Rodriguez is an 85-year-old client who presents to her health care provider with an exacerbation of heart failure. Anna reports increasing shortness of breath with self-care activities. She also shares that she is no longer going to the senior center because getting in and out of the car leaves her short of breath and fatigued. She also reports that her feet feel “heavy” and that she has gained 3 pounds in the last 1–2 weeks. Anna sleeps on two pillows and does not awaken during the night with shortness of breath. She has also had a persistent itchy, dry cough and asks if she has a respiratory infection. The cough is nonproductive, and Anna reports no fever, chills, achy feeling, congestion, or chest pain.

Anna reports following a low-sodium diet and does not engage in exercise. She is a nonsmoker and does not drink alcohol.

History
Heart failure with preserved ejection fraction
Hypothyroidism

Current Medications
Lisinopril 10 mg twice daily
Levothyroxine 50 mcg once daily

Table 19.16

Vital Signs		Physical Examination
Temperature:	98.2°F	Head, eyes, ears, nose, throat (HEENT): Within normal limits Neurological: Within normal limits Cardiovascular: No jugular venous distension, 1+ pitting edema of feet and ankles. S1 and S2 heard on heart auscultation. No S3 noted. Brisk capillary refill in nailbeds of hands and feet. Respiratory: Crackles auscultated in lung bases bilaterally Gastrointestinal: Abdominal sounds heard in all four quadrants, no tenderness, no distension Integumentary: Skin appropriate for age
Heart rate:	95 beats/min
Respiratory rate:	22 breaths/min
Blood pressure:	158/94 mm Hg
Height:	5'4"
Weight:	152 lb (up 7 lb per client)

Exercise \(\PageIndex{1}\)

The nurse is reviewing enalapril administration with Anna. Which instruction about this drug will the nurse provide?

Avoid green, leafy vegetables.

Do not take if your heart rate is less than 60 beats/minute.

Avoid salt substitutes that contain potassium.

Report feelings of depression.

Answer

Avoid salt substitutes that contain potassium.

Exercise \(\PageIndex{2}\)

The nurse notes that Anna has 1+ pitting edema in the feet and ankles, a recent weight gain, and crackles in her lung bases. The nurse anticipates that the provider will order which drug?

Digoxin

Furosemide

Hydralazine/isosorbide dinitrate

Valsartan

Answer

Furosemide