From the Guidelines
Yes, Lasix (furosemide) can contribute to hyponatremia, a condition characterized by abnormally low sodium levels in the blood, as it inhibits sodium reabsorption in the kidneys, leading to increased excretion of sodium and water through urine. Furosemide is a loop diuretic that is effective for treating conditions like heart failure, liver disease, and edema, but it can sometimes lead to excessive sodium loss 1. Hyponatremia typically develops when water excretion doesn't keep pace with sodium excretion, resulting in a dilutional effect.
Risk Factors and Symptoms
This risk is higher in certain populations, including:
- Elderly patients
- Those taking other medications that affect sodium levels
- Patients with heart failure, cirrhosis, or kidney disease
- Individuals on low-sodium diets Symptoms of hyponatremia may include:
- Headache
- Confusion
- Nausea
- Muscle weakness
- Seizures
- In severe cases, coma
Management and Monitoring
Regular monitoring of electrolyte levels is important for patients taking Lasix, especially when starting therapy or adjusting dosages 1. If hyponatremia develops, management may involve:
- Adjusting the Lasix dosage
- Modifying fluid intake
- Sodium supplementation depending on the severity and underlying cause As stated in the guidelines on the management of ascites in cirrhosis, hypovolaemic hyponatraemia during diuretic therapy should be managed by discontinuation of diuretics and expansion of plasma volume with normal saline 1.
Key Recommendations
The most recent and highest quality study recommends monitoring all patients initiating diuretics for adverse events, including hyponatremia, and considering discontinuation or dose reduction if adverse events occur 1. Additionally, fluid restriction to 1–1.5 L/day should be reserved for those who are clinically hypervolaemic with severe hyponatraemia (serum sodium <125 mmol/L) 1.
From the FDA Drug Label
As with any effective diuretic, electrolyte depletion may occur during furosemide therapy, especially in patients receiving higher doses and a restricted salt intake All patients receiving furosemide therapy should be observed for these signs or symptoms of fluid or electrolyte imbalance (hyponatremia, hypochloremic alkalosis, hypokalemia, hypomagnesemia or hypocalcemia)
Yes, Lasix (furosemide) can contribute to hyponatremia. The drug label warns of the possibility of electrolyte depletion, including hyponatremia, during furosemide therapy, especially in patients receiving higher doses and a restricted salt intake 2.
From the Research
Hyponatremia and Lasix (Furosemide)
- Hyponatremia is a condition where the serum sodium concentration is less than 135 mmol per liter, and it can be a predictor of death among patients with chronic heart failure and cirrhosis 3.
- The use of diuretics, such as furosemide (Lasix), can contribute to the development of hyponatremia, especially when used in high doses or in combination with other diuretics like spironolactone 4.
- A study published in 1993 found that thiazides were responsible for severe diuretic-induced hyponatremia in 94% of 129 reported cases, while furosemide was not associated with hyponatremia in any of the cases 5.
- However, a more recent study published in 2020 found that high doses of furosemide (250-500 mg) were significantly associated with hyponatremia in patients with heart failure, particularly when used in combination with spironolactone 4.
- The mechanism by which furosemide contributes to hyponatremia is not fully understood, but it may be related to its effect on the kidneys and the regulation of electrolyte balance 6, 7.
Risk Factors for Hyponatremia with Furosemide Use
- High doses of furosemide (250-500 mg) 4
- Combination use with spironolactone 4
- Advanced age 4
- Diabetes mellitus 4
- Alcohol consumption 4
Management of Hyponatremia
- The treatment of hyponatremia depends on the underlying cause and severity of the condition 3, 6, 7.
- In patients with heart failure, diuretic dose reduction may help avoid hyponatremia and improve clinical status and prognosis 4.
- The use of vasopressin receptor antagonists, such as tolvaptan, may be effective in increasing serum sodium concentrations in patients with euvolemic or hypervolemic hyponatremia 3, 6, 7.