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Urea for Treatment of Hyponatremia in Patients With SIAD Unresponsive to Fluid Restriction

ConditionSIAD - Syndrome of Inappropriate Antidiuresis
Trial statusRecruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age18+
SponsorUniversity of Turin, Italy

About this trial

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 criteria

This trial does not accept healthy volunteers

Qualifiers

Plasma sodium concentration <135 mmol/L

Plasma osmolality <300 mOsm/kg

Urine osmolality >100 mOsm/kg

Urine sodium concentration >30 mmol/L

Disqualifiers

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)

Trial design

Design model

Single group

Treatments tested in this trial

  • urea

    Dietary supplement

    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.

Treatment groups

20 Participants
are divided into 1 treatment group
Group A: Urea therapyExperimental treatment 1 intervention

Trial outcomes

Primary outcomes

1

Change in serum sodium levels

Change in serum sodium from baseline to assess the acute and chronic effectiveness of urea therapy in outpatients with SIAD not adequately compensated by fluid restriction (≤1500 mL/day)

Time frame
Baseline, day 1, day 21±4, day 42±4, and 10±2 days post urea discontinuation

Secondary outcomes

1

Changes in copeptin, NT-proBNP, and MR-proADM levels

Changes in copeptin, NT-proBNP, and MR-proADM levels from baseline to day 42±4 and after urea discontinuation at 10±2 days, to evaluate chronic neuroendocrine response to urea therapy

Time frame
Baseline, day 42±4, and 10±2 days post-therapy
2

Bioimpedance adaptation

Changes in intra- and extracellular fluid volumes as assessed by bioimpedance vector analysis (BIVA) from baseline to day 42±4 and after urea discontinuation at 10±2 days

Time frame
Baseline, day 42±4, and 10±2 days post-therapy
3

Bone turnover markers

Changes in serum C-terminal telopeptide (CTX) and N-terminal pro-peptide of type 1 collagen (PINP) from baseline to day 42±4 and after urea discontinuation at 10±2 days, to evaluate bone metabolism response to variation of serum sodium levels

Time frame
Baseline, day 42±4, and 10±2 days post-therapy
4

Cognitive performance

Changes in Montreal Cognitive Assessment (MoCA) scores from baseline to day 42±4, to evaluate the effect of sodium increase normalization on cognitive function

Time frame
Baseline and day 42±4

Other outcomes

Sponsors and contacts

Click on the lead sponsor to view all of their trials.

University of Turin, Italy

Lead sponsor

Source ClinicalTrials.gov
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