From the Guidelines
Urea is not recommended as a primary treatment for low sodium (hyponatremia) in most clinical settings. The management of hyponatremia depends on the severity, symptoms, and underlying cause of the condition. According to the 2021 practice guidance by the American Association for the Study of Liver Diseases 1, for patients with cirrhosis, mild hyponatremia (Na 126-135 mEq/L) without symptoms does not require specific management apart from monitoring and water restriction.
Key Considerations
- For moderate hyponatremia (120-125 mEq/L), water restriction to 1,000 mL/day and cessation of diuretics is recommended.
- Severe hyponatremia (<120 mEq/L) requires a more severe restriction of water intake with albumin infusion.
- Vasopressin receptor antagonists can be used with caution for a short term (≤30 days) to raise serum sodium in cirrhosis patients.
- Hypertonic saline is reserved for short-term treatment of patients with symptomatic or severe hyponatremia.
Treatment Goals
- The goal rate of increase of serum sodium is 4-6 mEq/L per 24-hour period, not to exceed 8 mEq/L per 24-hour period to ameliorate the risk of osmotic demyelination syndrome (ODS) 1.
- Multidisciplinary coordinated care may mitigate the risk of ODS in patients with severe hyponatremia undergoing liver transplantation. While urea can increase renal water excretion without increasing sodium excretion, its use is limited due to poor palatability and availability, and it should only be considered in specific circumstances under medical supervision, as it is not mentioned as a recommended treatment in the provided guidance 1.
From the Research
Urea for Low Sodium
- Urea can be used as a treatment for hyponatremia, particularly in patients with the syndrome of inappropriate antidiuretic hormone secretion (SIADH) and heart failure 2.
- The use of urea in treating hyponatremia is effective, but it has adverse effects such as poor palatability and gastric intolerance 2.
- In patients with low sodium levels, urea can help increase the serum sodium level, but it should be used with caution to avoid overly rapid correction, which can lead to osmotic demyelination 2.
Diagnosis and Management of Hyponatremia
- Hyponatremia is classified into three categories: hypovolemic, euvolemic, and hypervolemic, depending on the patient's fluid volume status 3, 2, 4.
- The management of hyponatremia depends on the underlying cause, severity of symptoms, and rate of onset 3, 2, 4.
- Treatment options for hyponatremia include fluid restriction, demeclocycline therapy, loop diuretics, and urea, as well as arginine vasopressin receptor antagonists for euvolemic and hypervolemic hyponatremia 3, 2, 5.
Treatment Options for Hyponatremia
- Urea and vaptans can be effective treatments for SIADH and hyponatremia in patients with heart failure, but they have adverse effects 2.
- Hypertonic saline is reserved for patients with severely symptomatic hyponatremia, and its use should be guided by the severity of symptoms and the rate of correction needed 2.
- Arginine vasopressin receptor antagonists are a new class of drugs that can be used to treat euvolemic and hypervolemic hyponatremia by promoting the excretion of free water 5.