Furosemide (Lasix) Nursing Considerations: Administration, Patient Teachings, and More

Nurse Beth, MSN

Furosemide (Lasix) Indications

Furosemide (Lasix) is used to treat acute pulmonary edema, pleural effusions, and volume overload of different etiologies, including the following ⁽¹⁾

Congestive heart failure
Ascites from cirrhosis or end-stage liver disease (ESLD)
Edema in renal failure
Nephrotic syndrome

Furosemide has antihypertensive effects ⁽¹⁾.

Table of Contents

Indications
Pharmacology
Contraindication/Precautions
Furosemide Administration
Furosemide Slow IV Push
Nursing Considerations
Nursing Assessment and Interventions
NCLEX Questions

Pharmacology

Furosemide is metabolized 100% by the kidneys ⁽²⁾.

Most loop diuretics reach peak serum concentrations within 0.5 to 2 hours of administration. Depending on the condition of the kidney, the heart, or the liver, the effects of the drug may last up to 8 hours. Furosemide's short half-life means it is dosed at least twice daily⁽²⁾.

Mechanism of Action

Furosemide is an inhibitor of electrolyte reabsorption from the proximal and distal tubules and the ascending loop of Henle. It increases renal excretion of water, sodium, chloride, magnesium, potassium, and calcium ⁽³⁾.

Contraindication/Precautions

Furosemide is contraindicated in patients with ⁽¹⁾

Anuria
Hypersensitivity to furosemide
Hepatic coma

Patients with sulfonamide allergy may also be allergic to furosemide.

Adverse Reactions/Side Effects

Furosemide causes several adverse side effects, especially in patients with chronic kidney disease ^{(1, 4)}.

Hypotension caused by diuresis and vasodilation
Hypokalemia
Hypocalcemia
Metabolic alkalosis
Hyperuricemia
Hypomagnesemia
Hyponatremia
Hyperglycemia
Increased BUN and serum creatinine
Increased serum glucose
Increased uric acid levels

Ototoxicity is an uncommon complication and occurs in patients who receive ^{(2, 5)}

High doses of the medication
Have kidney disease
Are older adults
Have concomitant use of aminoglycoside antibiotics

Interactions

Digoxin toxicity can occur in patients taking digoxin ⁽⁵⁾.
Signs of digoxin toxicity are anorexia, nausea, vomiting, muscle cramps, paresthesia, and confusion.
Concomitant use of cyclosporine is associated with an increased risk of gouty arthritis ⁽⁵⁾.
There is a risk of hearing loss if high doses of salicylates and furosemide are given concomitantly ⁽¹⁾.
May cause lithium toxicity ⁽¹⁾.
NSAIDs may cause increased BUN and serum creatinine ⁽¹⁾.
Nephrotoxicity of cisplatin may be enhanced ⁽¹⁾.

There is a risk of ototoxic effects with the concomitant use of:

Ethacrynic acid⁽¹⁾.
Aminoglycosides (especially in the presence of impaired renal function)^{(1, 4)}.

Furosemide Administration

Furosemide is available in oral, oral solution, and intravenous formulations.

Oral Dosage

Ultimately, the effective dose is determined by urine output response⁽²⁾. Dosage should be individualized according to the desired diuretic effect.

For edema

20–80 mg/day as a single dose initially
May repeat in 6–8 hr for insufficient diuresis
May increase the dose by 20–40 mg every 6–8 hr until the desired response

Maintenance doses may be given once or twice daily.

For antihypertensive effects

40 mg twice daily initially

The onset of oral furosemide is

30-60 minutes
Peak effect is at 1-2 hrs

Parenteral Dosage

Rapid diuresis is achieved with intravenous furosemide. Dosage should be individualized according to the desired diuretic effect.

Edema IM/IVP ⁽¹⁾

20–40 mg slowly ( over 1-2 minutes)
May repeat in 1–2 hr
May increase by 20 mg every 1–2 hr until the desired response is obtained

The maintenance dose may be given every 6–12 hrs.

Acute pulmonary edema IV⁽¹⁾

40 mg injected slowly intravenously (over 1 to 2 minutes).
After 1 hour dosage may be increased to 80 mg injected slowly intravenously (over 1 to 2 minutes)

Peak and onset ⁽¹⁾

Diuresis begins within five minutes of intravenous administration
Peak occurs approximately half an hour after the start of the effects
Diuretic effects last roughly two hours

Furosemide Slow IV Push

Furosemide drug inserts and drug books caution to administer furosemide slow IVP to avoid ototoxicity. However, there is a paucity of evidence suggesting that the administration rate of furosemide, when given IVP, causes ototoxicity.

Additionally, the definition of slow IVP varies widely.

What is slow IVP?

The manufacturer alternately defines slow IVP ⁽¹⁾ as:

10 mg/minute or
20 mg/minute or
40 mg/minute or
80 mg/minute

Conversely, continuous infusions are directed to run at no faster than 4 mg/minute ⁽¹⁾. However conventional practice is to administer furosemide IVP slowly and there is no harm in doing so.

Nursing Considerations

Oral tablets may be taken with food or milk to minimize gastric irritation. Tablets may be crushed if needed. Lasix comes in an oral solution.
Place patients on fall risk due to potential postural hypotension.
Ensure ambulatory patients do not flush the toilet after urinating, preventing accurate I&O. Provide a hat or urinal.
If patient has a foley, use a urometer for hourly measurements
Make sure to place the call light within easy reach for bedridden patients and give males a urinal. They will have urinary urgency.
Notify the monitor tech to be alert for PVCs or set alarm limits to notify

Nursing Assessment and Interventions

Assess for response to furosemide administration to see if fluid overload was reduced, or blood pressure decreased pulmonary congestion.

Assess for signs of volume overload:

Dyspnea and activity intolerance
Peripheral and dependent edema (sacral area if bedridden)
S3 gallop, bilateral crackles
Pulse oximetry readings

Monitor fluid changes

Measure I &O and daily weights
Maintain fluid restriction if ordered
Monitor urine output 30 minutes to 1 hour after IV push administration
Monitor BP for orthostatic hypotension

Monitor labs

Monitor for S&S of hypokalemia
Monitore BUN, creatinine and electrolytes
Obtain potassium and magnesium before and after rapid diuresis

Potential Diagnoses

Fluid or electrolyte imbalance.

Desired Outcomes

Decreased edema
Increased urinary output
Decreased blood pressure
Weight loss
Dyspnea relief

Patient Teaching

Nursing TIP: Patients often refer to furosemide as their "water pill" and may not know the name of the drug.

This medication causes frequent urination in large amounts for 1-2 hours after taking the medication. Plan out-of-the-house activities accordingly.
Take medication early at night or in the evening so sleep is not disturbed.
Change position slowly. You may feel dizzy when standing up suddenly.
Take potassium supplements as ordered.
Anticipate temporary hyperglycemia (patients with diabetes mellitus).
Avoid prolonged exposure to direct sun. It may cause photosensitivity.
Follow any salt and fluid restrictions.
Keep potassium-rich foods on hand (e.g., bananas, oranges, peaches, dried dates).
Check with your provider if you are breastfeeding.
Take with food or meals to prevent stomach upset.
Weigh daily at the same time, in the same clothing, and after urination.
Consider purchasing a smart scale to automatically communicate readings to your provider.

Notify your provider of the following:

Dizziness, muscle weakness, or cramps
Increasing shortness of breath or needing to sleep upright
Weight gain of more than 2 pounds in 1 day or 5 lbs in one week ⁽⁶⁾
Swelling in lower legs, ankles, and feet
Gout
Sensation of irregular heart beats

Go to the emergency department or urgent care for sudden, sustained shortness of breath.

Nursing TIP: When teaching patients, ask them to repeat back what you told them (called teach-back method) to ensure they understood.

NCLEX Questions

On the NCLEX, you are likely to be tested on the following key points.

Hypokalemia, hypomagnesia, and ototoxicity are potential adverse effects of furosemide
Foods that are rich in potassium include bananas, broccoli, and Swiss chard, avocados, spinach
Furosemide affects the ascending limb of the loop of Henle

Nursing pharmacology

Differentiate between loop diuretics (such as furosemide) and thiazide diuretics (such as hydrochlorothiazide)
Differentiate between potassium-sparing diuretics (such as spironolactone, an aldosterone inhibitor) and potassium-wasting diuretics (such as furosemide)

Anecdotal Experience

Furosemide is a wonder drug that decongests patients with fluid overload rapidly.

Hypomagnesemia and hypokalemia are the most severe side effects. Premature ventricular contractions (PVCs) can cause ventricular tachycardia and ventricular fibrillation, both of which are lethal arrhythmias.

If your patient develops PVCs, order magnesium and potassium levels stat and replace as ordered in the facility's replacement protocols or orders.

PVCs are a lethal arrhythmia but when caused by hypomagnesemia and hypokalemia respond well to IV magnesium or potassium replacement.

STAFF NOTE: Original Community Post

This article was created in response to a community post. The comments and responses have been left intact as they may be helpful. Here's the original post:

Quote

Can anybody tell me why Lasix needs to be pushed slowly? I keep getting different answers. I want to understand why it is that I have to push it over 1-2 minutes. Thank you.

References

1.Furosemide Injection insert. 2016. Hospira. Reference ID: 3989427 https://www.accessdata.fda.gov/drugsatfda_docs/label/2016/018667s036lbl.pdf

2. Novak, J. E., & Ellison, D. H. (2022). Diuretics in states of volume overload: core curriculum 2022. American Journal of Kidney Diseases. https://pubmed.ncbi.nlm.nih.gov/35190215/

3. Khan, T. M., Patel, R., & Siddiqui, A. H. (2022). Furosemide. In StatPearls. StatPearls Publishing.

4. Oh SW, Han SY. Loop Diuretics in Clinical Practice. Electrolyte Blood Press. 2015 Jun;13(1):17-21. https://doi.org/10.5049/EBP.2015.13.1.17

5. Ding, Dalian, Hong Liu, Weidong Qi, Haiyan Jiang, Yongqi Li, Xuewen Wu, Hong Sun, Kenneth Gross, and Richard Salvi. "Ototoxic effects and mechanisms of loop diuretics." Journal of otology 11, no. 4 (2016): 145-156. https://www.sciencedirect.com/science/article/pii/S1672293016300629

6. Daily Weights. Internet. Obtained Feb 23, 2023. American Association of Heart Failure Nurses AAHFN. https://www.aahfn.org/mpage/dailyweights