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The Influence of 5-Aminosalicylates on Thiopurine Metabolite Levels

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00167882
Recruitment Status : Completed
First Posted : September 14, 2005
Last Update Posted : September 11, 2006
Information provided by:
VU University Medical Center

Brief Summary:
The purpose of this study is to determine the influence of different 5-aminosalicylate concentrations on the metabolism of azathioprine or 6-mercaptopurine in patients with inflammatory bowel disease.

Condition or disease Intervention/treatment Phase
Crohn's Disease Ulcerative Colitis Inflammatory Bowel Disease Drug: 5-aminosalicylate (Pentasa, Ferring) Phase 4

Detailed Description:


The concomitant use of 5-aminosalicylates (5ASA) next to azathioprine (AZA) or 6-mercaptopurine (6MP) in the treatment of inflammatory bowel disease (IBD) may lead to an increased effectiveness of therapy as higher levels of the active metabolite of AZA/6MP (6-thioguaninenucleotides (6TGNs) are measured.


To determine the influence of 5-ASA compounds and its metabolites on the metabolites of AZA/6MP (6TGNs + 6-methylmercaptopurine (6MMP).


Patients with quiescent disease under AZA/6MP therapy are eligible. Patients will receive three succeeding regimes (5ASA 2 gram/5ASA 4 gram/ no 5ASA) of 4 weeks next to the standard AZA/6MP therapy. At the start and at the end of every regime 5ASA and its major metabolite (N-acetyl-5ASA) will be determined in serum next to the measurement of 6TGNs and 6MMP in erythrocytes. The safety will monitored by standard laboratory parameters every four weeks.


Patients with IBD in remission and unchanged AZA/6MP dosages for at least 4 weeks.


5ASA (Pentasa ® granules; Ferring) will be administered orally in dosages of 2 or 4 grams daily for a period of 4 weeks.


The rise or decrease in 6TGNs and 6MMP during the different 5ASA regimes. The evaluation of the safety of co-administrating 5ASA next to AZA/6MP.


Side effects of 5ASA use are limited and well known. Some case reports have described the potential risk of developing a myelodepression when AZA/6MP and 5ASA are given together due to the rise in 6TGNs. However, in daily practice both drugs are administered together frequently. The risks of the frequent blood draws are minimal and usually self-limiting (haematoma).

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Study Type : Interventional  (Clinical Trial)
Enrollment : 24 participants
Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: Single
Primary Purpose: Treatment
Study Start Date : July 2005
Study Completion Date : August 2006

Primary Outcome Measures :
  1. To determine the influence of 5-ASA compounds and its metabolites on the 6-TGN level during steady state AZA or 6-MP dosages

Secondary Outcome Measures :
  1. To determine the influence of 5-ASA compounds and its metabolites on the 6-MMP level during steady state AZA or 6-MP dose
  2. To determine the influence of 5-ASA compounds and its metabolites on the 6-TGMP, 6-TGDP and 6-TGTP levels during steady state AZA or 6-MP dosages
  3. To evaluate the safety of co-administrating 5-ASA and AZA or 6-MP in IBD patients

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 70 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Adult patients, aged between 18 - 70 years
  • Informed consent
  • Diagnosis of CD or UC for at least 6 months (histological and endoscopically confirmed)
  • Steady state AZA of 6-MP use (an unchanged thiopurine regime for at least 4 weeks)
  • Normal liver and kidney function (ALAT / AP / creatinin < 2 x upper normal limit)
  • Quiescent disease (HBI score ≤ 4 for CD or modified TLWI score ≤ 4 for UC)

Exclusion Criteria:

  • Bone marrow suppression (platelets / leucocytes < 1 x lower normal level)
  • Presence of active infection (fever and CRP > 1 x upper normal limit)
  • Anemia (hemoglobin < 6 mmol)
  • Known duodenal Crohn's disease interfering significantly with resorptive area
  • Small bowel surgery interfering significantly with resorptive area
  • Known intolerance to 5-ASA compounds
  • Current use of 5-ASA compounds
  • Use of 5-ASA compounds within the last 30 days
  • Concomitant use of allopurinol, ACE-inhibitors or furosemide
  • Pregnancy, expected pregnancy or lactation within 6 months

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00167882

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Maasland Hospital
Sittard, Netherlands
Sponsors and Collaborators
VU University Medical Center
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Principal Investigator: K.H.N. de Boer, MD VU University Medical Center
Layout table for additonal information Identifier: NCT00167882    
Other Study ID Numbers: 2005/28
First Posted: September 14, 2005    Key Record Dates
Last Update Posted: September 11, 2006
Last Verified: August 2006
Keywords provided by VU University Medical Center:
Crohn's disease
Ulcerative colitis
Inflammatory bowel disease
Additional relevant MeSH terms:
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Crohn Disease
Colitis, Ulcerative
Intestinal Diseases
Inflammatory Bowel Diseases
Gastrointestinal Diseases
Digestive System Diseases
Colonic Diseases
Pathologic Processes
Anti-Inflammatory Agents, Non-Steroidal
Analgesics, Non-Narcotic
Sensory System Agents
Peripheral Nervous System Agents
Physiological Effects of Drugs
Anti-Inflammatory Agents
Antirheumatic Agents