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Enteric Coating as a Factor in Aspirin Resistance

This study has been completed.
Irish Heart Foundation
Information provided by:
Royal College of Surgeons, Ireland Identifier:
First received: September 17, 2007
Last updated: September 28, 2009
Last verified: September 2009

Aspirin is an essential drug for the treatment of cardiovascular disease. The standard dose is 75mg per day (much lower than that for inflammation or fever). One of the side-effects of aspirin is a gastric ulcer which can be fatal. To prevent this it is common to use enteric-coated aspirin. This passes through the stomach intact and dissolves in the intestines. This prevents high levels of drug forming in the stomach reducing ulcer formation. Recently there is evidence of high levels of aspirin resistance, ie, patients who appear not to achieve the maximum benefit from aspirin. Clinical studies have shown a significant increase in mortality among these patients.

A recent study that we performed showed that enteric-coated aspirin is not as effective as plain aspirin. This was especially noticeable in heavier volunteers. In fact it appeared that enteric-coated aspirin only delivers 50mg aspirin instead of the full 75 mg. For volunteers resistant to enteric-coated aspirin simply switching them to plain aspirin solved the problem.

We propose to recruit patients on 75 mg enteric aspirin and test them for evidence of poor response to aspirin. Poor responders will then be given 75mg plain aspirin and tested for their response. Those that fail to respond will then receive 150 mg aspirin. If the results of the healthy volunteer study are replicated this would provide a very cheap and effective solution to a serious problem.

Condition Intervention
Cardiovascular Disease Drug: Plain aspirin

Study Type: Observational
Study Design: Observational Model: Cohort
Time Perspective: Prospective
Official Title: Enteric Coating as a Factor in Aspirin Resistance

Resource links provided by NLM:

Further study details as provided by Royal College of Surgeons, Ireland:

Biospecimen Retention:   Samples Without DNA
Serum samples will be collected and stored for later analysis

Enrollment: 250
Study Start Date: September 2007
Study Completion Date: December 2008
Primary Completion Date: December 2008 (Final data collection date for primary outcome measure)
Groups/Cohorts Assigned Interventions
All patients (acute or stable) presenting to a cardiovascular clinic and on aspirin.
Drug: Plain aspirin
Plain aspirin 75 mg or 150 mg

  Show Detailed Description


Ages Eligible for Study:   Child, Adult, Senior
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Non-Probability Sample
Study Population
Patients attending the cardiac outpatients clinic or the cat lab of Beaumont hospital, Dublin, Ireland

Inclusion Criteria:

  • Stable or unstable coronary artery disease
  • On aspirin

Exclusion Criteria:

  • Inability to give informed consent
  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: NCT00531362

Beaumont Hospital
Dublin, Ireland
Sponsors and Collaborators
Royal College of Surgeons, Ireland
Irish Heart Foundation
Principal Investigator: Dermot Cox, PhD Royal College of Surgeons
  More Information

Additional Information:
Responsible Party: Dermot Cox, Royal College of Surgeons in Ireland Identifier: NCT00531362     History of Changes
Other Study ID Numbers: RCSI1
Study First Received: September 17, 2007
Last Updated: September 28, 2009

Keywords provided by Royal College of Surgeons, Ireland:
Acute coronary syndromes

Additional relevant MeSH terms:
Cardiovascular Diseases
Anti-Inflammatory Agents, Non-Steroidal
Analgesics, Non-Narcotic
Sensory System Agents
Peripheral Nervous System Agents
Physiological Effects of Drugs
Anti-Inflammatory Agents
Antirheumatic Agents
Fibrinolytic Agents
Fibrin Modulating Agents
Molecular Mechanisms of Pharmacological Action
Platelet Aggregation Inhibitors
Cyclooxygenase Inhibitors
Enzyme Inhibitors
Antipyretics processed this record on September 20, 2017