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Urea

Also known as: Urea, Carbamide, CO(NH2)2

Overview

Urea, also known as carbamide, is a naturally occurring nitrogenous compound found in urine and synthesized by the liver. It is highly soluble in water and has a low molecular weight, facilitating easy absorption and metabolism. Primarily, urea is used medically to treat conditions like hyponatremia, particularly in the syndrome of inappropriate antidiuretic hormone secretion (SIADH). It is also widely used in agriculture as a nitrogen-rich fertilizer. The medical use of urea for SIADH is supported by observational studies and systematic reviews, which highlight its effectiveness in increasing serum sodium levels. However, the evidence base is limited by the absence of randomized controlled trials, which are needed to confirm these findings definitively. Urea's safety profile is generally favorable, with dysgeusia (distorted sense of taste) being the most commonly reported side effect.

Benefits

Urea is primarily beneficial for treating hyponatremia, specifically in patients with SIADH. A systematic review indicated that urea can increase serum sodium levels by an average of 9.6 mmol/L. This effect is particularly valuable in resource-limited settings where alternative treatments may not be readily available. The benefits are typically observed within 24 hours, with continued improvement over several days. While the effect size is clinically significant, the lack of randomized controlled trials (RCTs) means that the evidence is considered lower quality. The primary benefit is the correction of hyponatremia, which can alleviate symptoms associated with low sodium levels in the blood.

How it works

Urea increases serum osmolality, which helps correct hyponatremia by promoting water excretion without significant electrolyte loss. It primarily affects the renal system, enhancing diuresis without causing significant electrolyte imbalances. Urea does not have specific molecular targets but works through osmotic effects. It is well absorbed orally and rapidly distributed throughout the body. This mechanism helps to restore normal sodium levels in the blood, mitigating the effects of SIADH.

Side effects

Urea is generally considered safe, with minimal side effects. The most commonly reported side effect is dysgeusia (distorted sense of taste), occurring in a small percentage of users. Uncommon side effects are not consistently reported. Rare side effects are not well-documented. There are no major drug interactions reported, though caution should be exercised when using urea with other diuretics. Urea is generally not contraindicated, but its use should be under medical supervision. Pregnant and lactating women should consult healthcare professionals before use due to limited safety data. High doses may cause gastrointestinal discomfort. It is important to monitor serum electrolyte levels during urea treatment to avoid overcorrection of hyponatremia.

Dosage

For the treatment of SIADH, urea is typically started at a dose of 30-60 grams per day. The optimal dosage range generally falls between 30-90 grams per day, administered orally in divided doses. The maximum safe dose is not well defined, but high doses are associated with gastrointestinal discomfort. Absorption is not significantly affected by food intake. There are no specifically required cofactors. It is crucial to monitor serum sodium levels regularly to avoid overcorrection. Urea is not typically used as a dietary supplement and should only be used under medical supervision.

FAQs

Is urea safe to use?

Urea is generally safe when used under medical supervision. The most common side effect is dysgeusia. It's important to monitor serum electrolyte levels during treatment.

How quickly does urea work?

Benefits are typically observed within 24 hours, with continued improvement over several days as serum sodium levels increase.

What is the typical dosage of urea for SIADH?

The typical starting dose is 30-60 grams per day, with the optimal range between 30-90 grams per day, administered orally in divided doses.

Can urea be used as a dietary supplement?

No, urea is not typically used as a dietary supplement. It is primarily used for medical conditions like SIADH under medical supervision.

Are there any contraindications for urea use?

Urea is generally not contraindicated, but it should be used under medical supervision. Pregnant and lactating women should consult healthcare professionals before use.

Research Sources

https://pmc.ncbi.nlm.nih.gov/articles/PMC10616719/ – This systematic review of 23 studies involving 537 patients with SIADH found that urea increased serum sodium levels by a mean of 9.6 mmol/L, with few adverse effects. The median treatment duration was 5 days, highlighting urea's effectiveness in increasing serum sodium with minimal side effects, though the evidence is limited by the lack of randomized controlled trials.
https://pubmed.ncbi.nlm.nih.gov/39362395/ – This meta-analysis of observational studies found urea to be safe and effective for managing SIADH-induced hyponatremia, with a mean increase in serum sodium of 9.08 mmol/L. The study provides evidence for urea's effectiveness and safety in treating SIADH, but acknowledges the limitations due to its reliance on observational studies rather than randomized controlled trials.
https://journals.plos.org/plosone/article/file?type=printable&id=10.1371%2Fjournal.pone.0246922 – This meta-analysis on slow-release urea in dairy production showed improved performance and environmental impacts. While not directly related to human supplementation, the study highlights the effectiveness of slow-release urea in improving dairy production performance, though its findings are not applicable to human health.
https://www.mdpi.com/2076-2615/10/4/657 – This study focuses on the use of urea in ruminant nutrition, specifically addressing its role in optimizing nitrogen utilization and reducing environmental impact. It explores the benefits of urea as a cost-effective nitrogen source for livestock, contributing to sustainable agricultural practices.