Trial document





This trial has been registered retrospectively.
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  DRKS00000204

Trial Description

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Title

Does metamizol (dipyrone, Novalgin) affect the inhibition of platelet function by low-dose aspirin? Observational study in patients receiving analgesic treatment of chronic pain.

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Trial Acronym

MAI

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URL of the Trial

http://www.uniklinik-duesseldorf.de/deutsch/unternehmen/kliniken/klinikfransthesiologie/AmbulanzfrSchmerztherapieundPalliativmedizin/Forschung/page.html

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Brief Summary in Lay Language

Former research gives way to the assumption that there might be interactions between antiplatelet doses of aspirin and the analgesic drug metamizol (dipyrone) in such a way, that the inhibiting effect of aspirin on platelet function and thromboxane formation is weakened or lost (Hohlfeld et al, J Thromb Haemost 6: 166-173, 2008). We will examine this possible adverse drug interaction by means of blood samples, where it is planned to determine parameters of platelet function (aggregation, thromboxane synthesis) as well as the plasma concentration of metamizol.
Early after starting the trial an unexpected high rate of non-responder were recognized. For this reason 10 patients as a control-group were added. In this control-group the patients received Aspirin without Metamizol. A positive ethic commitment was given on March the 1st 2012 by the ethics committe of the medical faculty of the Heinrich-Heine-University Dusseldorf.

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Brief Summary in Scientific Language

Several non-steroidal antiphogistics and analgesics (NSAID) are known to affect or even offset the irreversible inhibition of platelet function induced by aspirin. Metamizol is routinely applied in the therapy of acute and chronic pain. Some of the patients receiving pain treatment show considerable comorbidities: Due to advanced age and other risk factors especially cardiovascular risks are increased with many patients, so that long-term treatment with low-dose aspirin (mostly 100 mg) are often routinely administered in addition to the pain treatment. This, however, implicates the possibility that aspirin-induced inhibition of platelet function is lost in chronic pain patients receiving metamizol. We would like to examine this possible interaction on the basis of an observational study. It is intended to collect a low quantity of blood (approximately 10ml) from the patients described above in order to examine whether aspirin-induced inhibition of platelet function is maintained during treatment with metamizol. In addition, we intend to determine the actual plasma concentrations of metamizol and examine their correlation with the effect of aspirin on platelet function.

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Organizational Data

  •   DRKS00000204
  •   2010/03/04
  •   [---]*
  •   yes
  •   Approved
  •   3271, Ethik-Kommission an der Medizinischen Fakultät der Heinrich-Heine-Universität Düsseldorf
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Secondary IDs

  •   U1111-1113-3946 
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Health Condition or Problem studied

  •   I25 -  Chronic ischaemic heart disease
  •   I67.2 -  Cerebral atherosclerosis
  •   I70.9 -  Generalized and unspecified atherosclerosis
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Interventions/Observational Groups

  •   Patients received aspirin and metamizol.
  •   Control-group: Patients received only aspirin.
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Characteristics

  •   Non-interventional
  •   Observational study
  •   Non-randomized controlled trial
  •   Open (masking not used)
  •   [---]*
  •   Other
  •   Other
  •   Other
  •   N/A
  •   No
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Primary Outcome

Measurement of thrombocyteaggregation, thromboxansynthesis and metamizolconcentration in plasma during the therapy with the following methods.
1. Wholeblood-Aggregation
2. Centrifugation to gain platelet rich plasma (PRP)
3. Aggregation of PRP
4. Centrifugation to gain platelet poor plasma (PPP)
5. in case of totally abolished aggregation washing of
platelets to remove dipyrone
6. Determination of thromboxane formation by
radioimmunoassay (RIA)
7. Measuring of patients' plasmaconcentration of
dipyrone

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Secondary Outcome

[---]*

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Countries of Recruitment

  •   Germany
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Locations of Recruitment

  • [---]*
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Recruitment

  •   Actual
  •   2009/09/11
  •   40
  •   Monocenter trial
  •   National
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Inclusion Criteria

  •   Both, male and female
  •   18   Years
  •   no maximum age
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Additional Inclusion Criteria

Minimum age: 18 years;
Cardiovascular disease with an increased risk of "atherothrombotic" events;
Treatment with low-dosed acetylsalicylic acid (75-150mg/day);
Duration of preceeding intake of aspirin: at least 7 days;
Patients receiving an analgesic treatment with metamizol (dosage: 10-20mg/kg KG, 2-4 times per day)

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Exclusion Criteria

In the preceding period of 7 days acute administration of aspirin at dosages of >150mg;
Concurrent treatment with other NSAIDs (e.g. diclofenac);
Additional treatment with other platelet function inhibitors (e.g. clopidogrel);
Treatment with anticoagulants (e.g. vitamin K antagonists, heparin) in therapeutic dosage;
Accompanying diseases which lead to relevant alterations of platelet function or haemostasis

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Addresses

  • start of 1:1-Block address primary-sponsor
    • Institut für Pharmakologie und Klinische Pharmakologie Heinrich Heine Universität Düsseldorf
    • Mr.  Prof. Dr. med.  Thomas  Hohlfeld 
    • 40225  Düsseldorf
    • Germany
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    • Klinik für Anästhesiologie Universitätsklinikum Düsseldorf
    • Ms.  Dr. med.  Andrea  Schmitz 
    • Moorenstraße 5
    • 40225  Düsseldorf
    • Germany
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    • Klinik für Anästhesiologie Universitätsklinikum Düsseldorf
    • Ms.  Dr. med.  Andrea  Schmitz 
    • Moorenstraße 5
    • 40225  Düsseldorf
    • Germany
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Sources of Monetary or Material Support

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    • Institut für Pharmakologie und Klinische Pharmakologie Heinrich Heine Universität Düsseldorf
    • Prof. Dr. med.  Thomas  Hohlfeld 
    • 40225  Düsseldorf
    • Germany
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    •   [---]*
    •   [---]*
    •   [---]*
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Status

  •   Recruiting complete, follow-up complete
  •   2010/11/22
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Trial Publications, Results and other Documents

  • [---]*
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* This entry means the parameter is not applicable or has not been set.