Research Project: Pilot Study on Oral Urea Use in Patients at High Risk of Kidney Stone Recurrence


In clinical practice, many patients are not able to modify their habits to achieve a high level of diuresis and fluid intake and therefore are at an elevated risk for stone recurrence. The investigators think that Ure-Na (osmotic agent) taking could help to increase urine volume and decrease urine concentration, which would be of benefit in the prevention of kidney stones.

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: N/A
    • Intervention Model: Single Group Assignment
    • Primary Purpose: Other
    • Masking: None (Open Label)
  • Study Primary Completion Date: April 2023


  • Drug: Ure-Na
    • Participants in the study will receive Oral Urea (Ure-Na) treatment at a dose of 30 grams per day (2 x 15 gram pouches per day) Treatment will continue for approximately 1 month.

Arms, Groups and Cohorts

  • Experimental: Open label
    • The study provides for a single group, which will be its own control (pre/post intervention study). Participants in the study will receive Oral Urea (Ure-Na) treatment at a dose of 30 grams per day (2 x 15 gram pouches per day) for 1 month

Clinical Trial Outcome Measures

Primary Measures

  • Change From Baseline in urine output at 1 week and 1 Month
    • Time Frame: 1 week and 1 month
    • variation in 24-hour diuresis and urine biochemistry

Participating in This Clinical Trial

Inclusion Criteria

  • 18 to 60 years of age – High risk for recurrence (1 or more of) Bilateral or complex stones, Recurrent stones, Family history (1st degree relative), Non-calcium stones, Solitary kidney or anatomical abnormality, Nephrocalcinosis, Systemic disease with risk of stones (tubular acidosis, cystinuria, etc.) – Diuresis < 1.8 L/24 hours despite recommendations from physicians and/or nutritionist at the kidney stone clinic (as documented in the previous 6 months) Exclusion Criteria:

  • Patient does not meet 1 of the 3 inclusion criteria – Pregnancy or breastfeeding – Lack of understanding about the protocol and effects of Ure-Na – Expected inability to adequately increase fluid intake on Ure-Na

Gender Eligibility: All

Minimum Age: 18 Years

Maximum Age: 60 Years

Are Healthy Volunteers Accepted: No

Investigator Details

  • Lead Sponsor
    • Centre hospitalier de l’Université de Montréal (CHUM)
  • Provider of Information About this Clinical Study
    • Sponsor


Dion M, Ankawi G, Chew B, Paterson R, Sultan N, Hoddinott P, Razvi H. CUA guideline on the evaluation and medical management of the kidney stone patient – 2016 update. Can Urol Assoc J. 2016 Nov-Dec;10(11-12):E347-E358. doi: 10.5489/cuaj.4218. Epub 2016 Nov 10.

Borghi L, Meschi T, Amato F, Briganti A, Novarini A, Giannini A. Urinary volume, water and recurrences in idiopathic calcium nephrolithiasis: a 5-year randomized prospective study. J Urol. 1996 Mar;155(3):839-43.

Soupart A, Coffernils M, Couturier B, Gankam-Kengne F, Decaux G. Efficacy and tolerance of urea compared with vaptans for long-term treatment of patients with SIADH. Clin J Am Soc Nephrol. 2012 May;7(5):742-7. doi: 10.2215/CJN.06990711. Epub 2012 Mar 8.

Berl T. Impact of solute intake on urine flow and water excretion. J Am Soc Nephrol. 2008 Jun;19(6):1076-8. doi: 10.1681/ASN.2007091042. Epub 2008 Mar 12.

Decaux G, Brimioulle S, Genette F, Mockel J. Treatment of the syndrome of inappropriate secretion of antidiuretic hormone by urea. Am J Med. 1980 Jul;69(1):99-106.

Verbalis JG, Baldwin EF, Neish PN, Robinson AG. Effect of protein intake and urea on sodium excretion during inappropriate antidiuresis in rats. Metabolism. 1988 Jan;37(1):46-54.

Nayan M, Elkoushy MA, Andonian S. Variations between two 24-hour urine collections in patients presenting to a tertiary stone clinic. Can Urol Assoc J. 2012 Feb;6(1):30-3. doi: 10.5489/cuaj.11131.

Clinical trials entries are delivered from the US National Institutes of Health and are not reviewed separately by this site. Please see the identifier information above for retrieving further details from the government database.

At, we keep tabs on over 200,000 clinical trials in the US and abroad, using medical data supplied directly by the US National Institutes of Health. Please see the About and Contact page for details.