Does Omeprazole Decrease Intestinal Calcium Absorption?

University of Wisconsin, Madison23 enrolled

Overview

The purpose of this study is to measure the effect of omeprazole on intestinal calcium absorption in postmenopausal women.

Existing literature makes it unclear whether proton pump inhibitor therapy truly decreases intestinal calcium absorption. Up to 25 postmenopausal women will participate in this study. The primary study outcome is the change in intestinal calcium absorption following omeprazole therapy 40 mg daily for 30 days. The secondary outcomes include the change in urine n-telopeptide. We will interview women and review their medical records to determine eligibility. Eligible subjects will undergo three calcium absorption studies. The first 2 studies will determine the monthly variation in calcium absorption, while the 3rd study will occur after taking 40 mg of omeprazole daily for 30 days. Women will present to the research unit in the early morning and receive an oral and intravenous calcium tracer with breakfast. Over the next 24 hours, we will collect all urine for measurement of its calcium content. During the first stay, we will measure each subject's gastric pH by collecting gastric fluid from a temporary nasogastric tube. In consenting subjects we will collect one tube of blood, isolate its DNA.

Study Type

INTERVENTIONAL

Allocation

NON_RANDOMIZED

Masking

NONE

Enrollment

Conditions

Osteoporosis Achlorhydria GERD Hip Fracture

Interventions

OmeprazoleDRUG

40 mg po qAM one-half hour before breakfast for 30 days

Eligibility

Sex: FEMALEHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Women at least 5 years past menopause, defined as the last date of menses Exclusion Criteria: * Allergy/Intolerance to orange juice * Allergy/Intolerance to omeprazole or other PPI therapy * Use of drugs that interact with omeprazole including oral anti-fungal agents, coumadin, diazepam, phenytoin \& tacrolimus * Use of antacids, PPI or H2-blocker therapy within the past two months * Intestinal conditions associated with malabsorption or low gastric acid levels including Crohn's Disease, ulcerative colitis, pernicious anemia, bacterial overgrowth, celiac sprue, chronic diarrhea or use of antibiotics within the past month * Known Stage 4 or 5 Chronic Kidney Disease, defined as an estimated GFR \<30 cc/minute * Use of medications known to interfere with calcium metabolism, including oral steroids or anticonvulsants

Locations (1)

University of Wisconsin Hospital and Clinics

Madison, Wisconsin, United States

Outcomes

Primary Outcomes

Change in Intestinal Calcium Absorption From Baseline to One Month

percent calcium absorption

Time frame: change in calcium absorption from baseline to 1 month

Secondary Outcomes

Change in Bone Resorption From Baseline to 1 Month

urine n-telopeptide (normalized to creatinine levels)

Time frame: change in bone resorption from baseline to 1 month

Data from ClinicalTrials.gov

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