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Pharmacology · chapter 34 · Diuretic Drugs

Loop Diuretics

The 14 things this section of the textbook says that you are most likely to be asked about — quoted word for word, not retold. Then 6 practice questions with the reasoning.

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Key points

  1. Most prescribed diuretic class

    Loop diuretics are the most frequently prescribed type of diuretic drug. They are used to treat fluid volume excess and edema associated with heart failure, hypertension, cirrhosis, and renal disease.

  2. Where loop diuretics act

    Loop diuretics increase urinary output by blocking the reabsorption of sodium in the (thick) ascending loop of Henle.

  3. Potassium, calcium and magnesium losses

    Blocking the NKCC2 cotransporter blocks potassium reabsorption and triggers calcium and magnesium losses.

  4. Bumetanide for hard-to-treat clients

    Bumetanide is used to treat clients who do not respond to other loop diuretics, have severe renal disease, or require larger diuretic doses (Sidhu Puckett, 2023).

  5. Main adverse effect: electrolyte imbalance

    Loop diuretics primarily cause diuresis-induced electrolyte imbalances (Huxel et al., 2023). These alterations are more common in older adults and clients with inadequate fluid intake.

  6. Common and metabolic adverse effects

    Other common adverse effects include headache, dizziness, and postural hypotension. Metabolic effects may include hyperlipidemia, metabolic alkalosis, and hyperglycemia due to impaired glucose tolerance.

  7. Ototoxicity from fast IV

    Less common reactions include impotence, thrombocytopenia due to the secretion of antibodies, thrombotic events related to hypovolemia, and ototoxicity due to rapid intravenous administration.

  8. Sulfa allergy and contraindications

    Clients who are allergic to sulfa may possibly experience a mild reaction when using loop diuretics. Severe dehydration or anuria is a contraindication to any diuretic (Arumugham Shahin, 2023).

  9. Fall risk in older adults

    Special Considerations Use of Diuretics in Older Adults Research indicates that older adults have an increased risk of falling associated with diuretic use.

  10. Furosemide with digoxin

    Clients taking both furosemide and digoxin must be monitored for signs of digoxin toxicity, including bradycardia, nausea, vomiting, visual changes (halos), and cardiac arrhythmias.

  11. Loop diuretics with lithium

    Clients taking loop diuretics as well as lithium must be monitored for toxic blood levels of lithium carbonate, which can develop because diuretics inhibit the kidneys’ excretion of the drug.

  12. Check blood pressure and heart rate

    Assess the client’s blood pressure and heart rate before the initial dose and then intermittently during drug therapy on an ongoing basis to monitor for orthostatic hypotension.

  13. Give IV furosemide slowly

    A bolus dose should be administered slowly over 1–2 minutes. Rapid infusion rates of loop diuretics may trigger temporary or permanent hearing loss in susceptible clients.

  14. Diet teaching

    Follow a modified sodium diet with moderate intake of potassium-rich foods to counteract potassium losses. Avoid potential food interactions, including black licorice and alcohol.

Terms to know

Furosemide
Furosemide, a frequently prescribed loop diuretic, treats edematous conditions and fluid volume excess in heart failure, liver failure, and acute and chronic renal disease, including nephrotic syndrome (Khan et al., 2023).
Torsemide
Torsemide exhibits a stronger diuretic effect than furosemide does (Yifan et al., 2021).

Practice questions

Stuck on select-all-that-apply? How to take them one option at a time.

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Every question here, with the answer

  1. A nurse is preparing to give furosemide as an IV bolus. How should the nurse give it?

    1. Push it as fast as possible to get a quick diuresis.
    2. Give it only at bedtime.
    3. Give it slowly over 1–2 minutes.
    4. Mix it with the client's digoxin dose.

    Answer: Give it slowly over 1–2 minutes.

    A furosemide bolus is given slowly over 1–2 minutes because rapid infusion can cause temporary or permanent hearing loss. Mixing with other drugs or night dosing is not supported; night dosing causes nocturia.

  2. A client takes furosemide and digoxin. Which finding should the nurse report as a possible sign of digoxin toxicity?

    1. Seeing halos around lights
    2. Mild thirst
    3. Increased urine output
    4. Warm, dry skin

    Answer: Seeing halos around lights

    Clients taking furosemide and digoxin are monitored for digoxin toxicity: bradycardia, nausea, vomiting, visual changes such as halos, and arrhythmias. Increased urine output is the expected diuretic effect.

  3. Which assessments should the nurse perform for a client receiving a loop diuretic? Select all that apply.

    1. Urine output
    2. Electrolyte laboratory results
    3. Serum albumin before every dose
    4. Blood pressure and heart rate before the first dose
    5. Daily body weight

    Answer: Urine output, Electrolyte laboratory results, Blood pressure and heart rate before the first dose, Daily body weight

    Nursing implications include checking blood pressure and heart rate, body weight, urine output and electrolyte results. Checking albumin before every dose is not part of the listed care.

  4. A client with bipolar disorder takes lithium and is prescribed a loop diuretic. Why does the nurse monitor this client closely?

    1. Lithium levels can rise to toxic levels because the diuretic reduces its excretion.
    2. Lithium causes hyperkalemia with loop diuretics.
    3. The diuretic makes lithium ineffective.
    4. Lithium blocks the diuretic effect.

    Answer: Lithium levels can rise to toxic levels because the diuretic reduces its excretion.

    Diuretics inhibit the kidneys' excretion of lithium, so blood levels can become toxic. The other options describe effects the section does not state.

  5. A nurse is teaching a client who is going home on a loop diuretic. Which statements show the client understood? Select all that apply.

    1. "I will take my dose at bedtime so it works overnight."
    2. "If I feel better, I can lower my own dose."
    3. "I will avoid black licorice and alcohol."
    4. "I will eat some potassium-rich foods."
    5. "I will get up slowly from the bed or chair."

    Answer: "I will avoid black licorice and alcohol.", "I will eat some potassium-rich foods.", "I will get up slowly from the bed or chair."

    Clients should avoid black licorice and alcohol, change position slowly, and eat moderate potassium-rich foods. They should not take the drug at night or self-adjust the dose.

  6. An older adult client started a loop diuretic. Which safety intervention is most important?

    1. Restrict all fluids to prevent edema.
    2. Give the dose at night.
    3. Encourage a high-sodium diet.
    4. Implement fall precautions.

    Answer: Implement fall precautions.

    Older adults have an increased risk of falling with diuretic use, from orthostatic hypotension, more trips to the bathroom and electrolyte changes. Restricting all fluids risks dehydration, and night dosing and high sodium are against the teaching.

Where every quote comes from

Section 34.2 Loop Diuretics of Pharmacology for Nurses by Tina Barbour-Taylor, Leah Mueller (Sabato), Donna Paris, Dorie Weaver, OpenStax, 2024. Read the whole section free at openstax.org.

The textbook is licensed under CC BY-NC-SA 4.0. This page quotes it word for word and adds the headings, the order and the practice questions; references to the book's figures and stray spaces left by its formatting are removed. The page is shared under the same licence. Nothing here is sold.