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Does Omeprazole Decrease Intestinal Calcium Absorption?

This study has been completed.
Information provided by (Responsible Party):
University of Wisconsin, Madison Identifier:
First received: December 19, 2007
Last updated: February 14, 2013
Last verified: February 2013
The purpose of this study is to measure the effect of omeprazole on intestinal calcium absorption in postmenopausal women.

Condition Intervention Phase
Osteoporosis Achlorhydria GERD Hip Fracture Drug: Omeprazole Phase 4

Study Type: Interventional
Study Design: Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Official Title: Does Omeprazole Decrease Intestinal Calcium Absorption?

Resource links provided by NLM:

Further study details as provided by University of Wisconsin, Madison:

Primary Outcome Measures:
  • Change in Intestinal Calcium Absorption From Baseline to One Month [ Time Frame: change in calcium absorption from baseline to 1 month ]
    percent calcium absorption

Secondary Outcome Measures:
  • Change in Bone Resorption From Baseline to 1 Month [ Time Frame: change in bone resorption from baseline to 1 month ]
    urine n-telopeptide (normalized to creatinine levels)

Enrollment: 23
Study Start Date: January 2008
Study Completion Date: December 2010
Primary Completion Date: December 2008 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Experimental
Subjects will receive omeprazole 40 mg daily for 30 days
Drug: Omeprazole
40 mg po qAM one-half hour before breakfast for 30 days
Other Names:
  • Losec
  • Prilosec

Detailed Description:

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.


Ages Eligible for Study:   Child, Adult, Senior
Sexes Eligible for Study:   Female
Accepts Healthy Volunteers:   Yes

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
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT00582972

United States, Wisconsin
University of Wisconsin Hospital and Clinics
Madison, Wisconsin, United States, 53792
Sponsors and Collaborators
University of Wisconsin, Madison
Principal Investigator: Karen E Hansen, MD Univeristy of Wisconsin School of Medicine and Public Health
  More Information

Responsible Party: University of Wisconsin, Madison Identifier: NCT00582972     History of Changes
Other Study ID Numbers: H-2007-0179
Study First Received: December 19, 2007
Results First Received: July 6, 2012
Last Updated: February 14, 2013

Keywords provided by University of Wisconsin, Madison:
Calcium Absorption
Fractional Calcium Absorption
Stable Calcium Isotopes
Proton Pump Inhibitor
Intestinal Absorption of Calcium

Additional relevant MeSH terms:
Hip Fractures
Bone Diseases, Metabolic
Bone Diseases
Musculoskeletal Diseases
Femoral Fractures
Fractures, Bone
Wounds and Injuries
Hip Injuries
Leg Injuries
Stomach Diseases
Gastrointestinal Diseases
Digestive System Diseases
Acid-Base Imbalance
Metabolic Diseases
Calcium, Dietary
Bone Density Conservation Agents
Physiological Effects of Drugs
Anti-Ulcer Agents
Gastrointestinal Agents
Proton Pump Inhibitors
Enzyme Inhibitors
Molecular Mechanisms of Pharmacological Action processed this record on September 21, 2017