Indapamide to reduce urinary calcium in post-surgical hypoparathyroidism

Treatment With Indapamide in Patients With Post-Surgical Hypoparathyroidism

This trial will test whether taking indapamide once daily for 14 days lowers urinary calcium in adults with chronic post-surgical hypoparathyroidism.

Quick facts

• Phase: PHASE4
• Study type: Interventional
• Enrollment: 24 (estimated)
• Ages: 18 Years and up
• Sex: All
• Sponsor: University of Aarhus (other)
• Locations: 1 site (Aarhus)
• Trial ID: NCT07034677 on ClinicalTrials.gov

What this trial studies

Adults with chronic post-surgical hypoparathyroidism receive indapamide 1.5 mg sustained release or placebo for 14 days while clinicians monitor blood chemistry and urine output. Participants complete weekly blood tests and 24-hour urine collections every two weeks to track calcium and electrolyte changes. The main outcome is change in urinary calcium excretion after the treatment period. The protocol targets patients on stable active vitamin D therapy to see if indapamide can reduce hypercalciuria without causing significant electrolyte or blood pressure problems.

Who should consider this trial

Good fit: Adults (≥18) with chronic (over 1 year) post-surgical hypoparathyroidism who require ≥1 µg/day active vitamin D, have ionized calcium 1.15–1.25 mmol/L, adequate 25(OH)D and magnesium levels, and eGFR ≥30 ml/min/1.73 m2 are ideal candidates.

Not a fit: Patients with eGFR <30 ml/min/1.73 m2, low plasma potassium (<3.5 mmol/L), symptomatic hypotension or systolic BP <100 mmHg, recent or active non-thyroid cancer, pregnancy/planning/breastfeeding, or other disorders affecting calcium metabolism are unlikely to benefit or are excluded.

Why it matters

Potential benefit: If successful, indapamide could reduce urinary calcium loss and lower the risk of kidney stones or renal calcium-related complications in these patients.

How similar studies have performed: Thiazide and thiazide-like diuretics have a well-established effect of lowering urinary calcium in other conditions, but controlled data specifically testing indapamide in post-surgical hypoparathyroidism are limited.

Eligibility criteria

Inclusion Criteria:

1. Chronic post surgical hypoparathyroidism diagnosed \> 1 year ago
2. Age ≥ 18 years
3. Require treatment with active vitamin D ≥ 1 µg/day
4. Ionized plasma calcium between 1.15-1.25 mmol/L
5. 25(OH)D vitamin ≥ 50 nmol/L
6. Plasma magnesium \> 0.65 mmol/L
7. Able to read and understand Danish
8. Willing and able to sign the informed consent form

Exclusion Criteria:

1. Estimated glomerular filtration rate (eGFR) \< 30 ml/min/1.73 m3
2. Active cancer or former (except thyroid and basal cell skin) cancer treatment \< 1 year ago
3. Pregnancy, pregnancy plans, or breastfeeding \< 1 year ago
4. Abnormal arterial pressure at time of screening defined as symptomatic hypotension or systolic blood pressure \< 100 mmHg
5. Plasma potassium \< 3.5 mmol/L
6. Any current disease that might affect the calcium metabolism such as but not limited to:

   1. Recent prolonged immobility
   2. Untreated diabetes (HbA1c \> 53 mmol/mol)
   3. Severe liver disease or hepatic encephalopathy
   4. Untreated thyroid disease
7. Current disease that might affect gastrointestinal absorption
8. Use of medications such as lithium or diuretics within 4 weeks prior to start of treatment
9. Known allergy or sensitivity to Indapamide, its excipients or sulfonamides
10. Known galactosemia, lactase deficiency, or glucose-galactose malabsorption

Where this trial is running

Aarhus

• Department of Endocrinology and Internal Medicine — Aarhus, Denmark (RECRUITING)

Study contacts

• Study coordinator: Sarah Thornhøj, MD

Conditions: Hypoparathyroidism Post-surgical, hypoparathyroidism, indapamide, hypercalciuria