Urea for Chronic Hyponatremia: A Pilot Study
This study is examining how a dietary supplement called urea can be used to treat low blood sodium level. Low blood sodium level is a common problem and some studies show that many patients with low blood sodium level suffer from brain fog and/or loss of balance. Unfortunately, it is unknown at this point what the best treatment is for low blood sodium level. With this pilot research study, the investigators are hoping to learn more about whether urea is safe to take, whether patients can tolerate taking urea for several weeks, whether urea increases blood sodium level, and whether urea can help prevent the brain fog and/or loss of balance that some patients with low blood sodium level suffer from. The information obtained with this study is intended to be used to design a larger study in the future to get a definite answer whether urea is beneficial for patients with low blood sodium level.
• Age ≥18 years
• Attended ≥1 visit at a University of Pittsburgh Medical Center (UPMC) outpatient clinic within the prior 12 months
• Chronic hyponatremia with a history of ≥ 2 sequential plasma sodium concentration (PNa) between 125 mmol/L and 132 mmol/L performed ≥ 14 days apart within the last 12 months with most recent PNa ≤ 132 mmol/L prior to screening
• Patients are ambulatory without the need for any assist device (e.g., cane, walker)
• Mini-mental state examination (MMSE) score ≥ 25
• Diagnosis of SIADH established by the Bartter and Schwartz criteria as follows:
• Hyponatremia with a PNa between 125 mmol/L and 132 mmol/L
• Plasma osmolality < 275 mOsm/kg
• Clinical euvolemia
• Urine osmolality > 100 mosm/kg
• Urine Na ≥ 20 mmol/L
• Intact adrenal function (i.e., morning plasma cortisol value ≥15 μg/dL, or negative corticotropin stimulation test)
• Normal thyroid stimulating hormone (TSH) level (i.e., TSH between 0.3 to 5 μIU/mL)
• eGFR >= 45 ml/min/1.73 m2)