Can Furosemide (Lasix) increase ammonia levels?

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Last updated: April 7, 2025View editorial policy

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From the Guidelines

Lasix (furosemide) can potentially elevate ammonia levels in some patients, particularly those with liver disease, due to its diuretic effects leading to dehydration and electrolyte imbalances. This loop diuretic works by increasing urine output, which can lead to dehydration and electrolyte imbalances. When a patient becomes dehydrated, the kidneys may reduce blood flow to conserve water, potentially worsening liver function in those with pre-existing liver disease. Additionally, Lasix can cause hypokalemia (low potassium) and metabolic alkalosis, both of which can indirectly contribute to increased ammonia levels, as noted in the management of adult patients with ascites due to cirrhosis 1.

In patients with cirrhosis or hepatic encephalopathy, Lasix should be used cautiously and with close monitoring of ammonia levels, electrolytes, and hydration status. The typical dose of Lasix ranges from 20-80 mg daily for most conditions, but dosing should be individualized based on the patient's condition and response. Key considerations include:

  • Monitoring for signs of dehydration and electrolyte imbalances
  • Adjusting the diuretic regimen as needed to minimize the risk of elevated ammonia levels
  • Providing supportive treatments like lactulose to reduce ammonia if necessary
  • Being aware of the potential for azotemia with intravenous furosemide, as highlighted in the updated management guidelines 1.

If a patient on Lasix develops confusion, lethargy, or other signs of elevated ammonia, healthcare providers should evaluate ammonia levels and consider adjusting the diuretic regimen or providing supportive treatments. The most recent guidelines on the management of adult patients with ascites due to cirrhosis support the cautious use of Lasix, emphasizing the importance of monitoring and individualized care 1.

From the Research

Lasix and Ammonia Levels

  • The relationship between Lasix (furosemide) and ammonia levels is not directly addressed in the provided studies.
  • However, study 2 discusses the adverse reactions of furosemide in patients with cirrhosis of the liver, including electrolyte disturbances and volume depletion, but does not mention ammonia levels.
  • Study 3 investigates the treatment of hepatic encephalopathy (HE) with polyethylene glycol (PEG) 3350 electrolyte solution and lactulose, and finds that ammonia level or reduction did not correlate with HE grades.
  • Study 4 reviews the clinical impact of hyperammonemia in cirrhosis and the utility of serum ammonia testing, but does not discuss the effect of Lasix on ammonia levels.
  • Studies 5 and 6 discuss the pathophysiology and treatment of hepatic encephalopathy, including the role of ammonia, but do not mention Lasix.

Furosemide-Induced Adverse Reactions

  • Study 2 reports that furosemide-induced coma occurred in 11.6% of patients with cirrhosis of the liver, and was more frequent in patients with prior hepatic encephalopathy.
  • The study suggests that higher total doses of furosemide, hyperbilirubinemia, prolonged prothrombin time, and longer hospital stay were associated with higher frequencies of adverse reactions to furosemide.
  • However, the study does not provide information on the effect of furosemide on ammonia levels.

Hepatic Encephalopathy and Ammonia

  • Studies 3, 4, 5, and 6 discuss the relationship between hepatic encephalopathy and ammonia, including the role of ammonia in the pathophysiology of HE and the utility of serum ammonia testing.
  • However, none of these studies provide information on the effect of Lasix on ammonia levels.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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