Urea for Treatment of Hyponatremia in Patients With SIAD Unresponsive to Fluid Restriction
Efficacy of Oral Urea Supplementation in Patients With SIAD Not Adequately Controlled With Fluid Restriction
University of Turin, Italy
20 participants
Sep 12, 2024
INTERVENTIONAL
Conditions
Summary
Hyponatremia due to SIAD is frequently insufficiently corrected by fluid restriction alone, which remains the first-line therapy but is often poorly tolerated. Urea supplementation is recommended as second-line therapy. This prospective study evaluates the effectiveness of oral urea supplementation in patients with chronic SIAD and persistent hyponatremia despite fluid restriction.
Eligibility
Inclusion Criteria9
- Confirmed diagnosis of SIAD established prior to study inclusion, defined as:
- Plasma sodium concentration <135 mmol/L
- Plasma osmolality <300 mOsm/kg
- Urine osmolality >100 mOsm/kg
- Urine sodium concentration >30 mmol/L
- Intact adrenal and thyroidal function and no use of diuretics in the last 4 weeks
- Clinical euvolemia, defined as an absence of signs of hypovolemia (orthostasis, tachycardia, decreased skin turgor, dry mucous membranes) or hypervolemia (edema, ascites)
- Fulfillment of all diagnostic criteria at baseline (day 0) was not mandatory, as the diagnosis of SIAD had already been established prior to study inclusion based on overall clinical assessment.
- \- Written informed consent obtained
Exclusion Criteria9
- Chronic hypotonic hyponatremia secondary to another etiology
- Presence of moderate to severe symptoms attributable to plasma hypotonicity
- Severe hypotonic hyponatremia (serum sodium <120 mmol/L)
- Another ongoing drug treatment for hyponatremia (including vaptans and salt tablets)
- Severe hepatic insufficiency
- eGFR <45 mL/min/1.73 m²
- Pregnancy or breastfeeding
- Known allergy or intolerance to urea
- Patient refusal or inability to provide written informed consent
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Interventions
Patients with persistent hyponatremia (sodium corrected for glucose \<135 mmol/L) after ≥1 week of fluid restriction (≤1500 mL/day) will receive urea 30 g/day (2 sachets; 1 in the morning and 1 in the evening) dissolved in water, while maintaining fluid restriction ≤1500 mL/day. Blood and urine evaluations will be performed at day 1, day 21±4 and day 42±4, with additional assessments (Montreal Cognitive Assessment \[MoCA\] questionnaire and bioelectrical impedance vector analysis \[BIVA\]) at selected visits. Urea dose adjustments will be based on serum sodium at day 21±4: 45 g/day if Na 130-134 mmol/L, or 60 g/day if Na \<130 mmol/L (maximum 60 g/day). In case of intolerance, the dose will be reduced by one sachet from the planned dose. After day 42±4, urea will be discontinued. A final evaluation will be performed 10±2 days after discontinuation.
Locations(1)
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NCT07528365