Optimal HCTZ Cessation for Diagnosis of Hyperparathyroidism



Status:Completed
Conditions:Endocrine
Therapuetic Areas:Endocrinology
Healthy:No
Age Range:18 - Any
Updated:1/10/2018
Start Date:May 2015
End Date:September 13, 2017

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Optimal Hydrochlorothiazide Cessation in Diagnosis of Hyperparathyroidism

Primary hyperparathyroidism (PHPT) is the most common cause of hypercalcemia in the
ambulatory setting. PHPT may be cured with surgery and indications for intervention have been
defined and include urinary calcium/creatinine clearance. Hydrochlorothiazide (HCTZ), the
most commonly prescribed medication for hypertension, reduces urinary calcium excretion and
confounds urinary testing. As a result, it is universally recommended that thiazide diuretics
be stopped in advance of urinary testing. To date, no studies are available to provide
evidence-based guidance as to how long HCTZ must be held for urinary calcium excretion to
return to steady state in PHPT. The objective of this study is to serially calculate urinary
calcium/creatinine clearance ration in patients with suspected PHPT while holding HCTZ to
determine the minimum duration of medication cessation necessary for urinary calcium
clearance to reach steady state.

In this study, adult patients will submit serum and 24 hour urine samples prior to HCTZ
cessation and at the following intervals after cessation: 4-6 days, 14-16 days, 28-30 days,
adn 90-92 days. To minimize confounding variable, patients will take supplemental Vitamin D
and Calcium, monitor their daily calcium intake, and monitor blood pressure weekly.
Alternative, non-diuretic, antihypertensive medication(s) may be prescribed at the discretion
of the enrolling provider.

Inclusion Criteria:

1. Elevated calcium on at least two separate draws with coexistent elevated parathyroid
hormone (PTH) on at least one occasion.

2. Taking Hydrochlorothiazide for hypertension

3. Following a "wash period", patients must have a normal range 25-hydroxy Vitamin D
level, thyroid stimulation hormone (TSH) and serum magnesium levels.

4. Controlled blood pressure

5. Willingness to comply with serial sampling

6. English as the primary language

7. Adults 18 years and older

Exclusion Criteria:

1. Unable to cease Hydrochlorothiazide for any reason

2. Congestive heart failure

3. Renal insufficiency (GFR <60)

4. Cardiovascular event in the last 3 months - include myocardial infarction, new onset
atrial fibrillation, and new onset bundle branch block

5. Take lithium or other diuretic medication in last 3 months

6. Positive family history of familial hypocalciuric hypercalcemia (FHH)
We found this trial at
1
site
Columbia, Missouri 65211
(573) 882-2121
Principal Investigator: Robert P Zitsch, M.D.
Phone: 573-882-2549
University of Missouri T he University of Missouri was founded in 1839 in Columbia, Mo.,...
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from
Columbia, MO
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