Pharmacy World and Science

, Volume 24, Issue 5, pp 201–204 | Cite as

The potential interaction between oral anticoagulants and acetaminophen in everyday practice

  • P.M.L.A. van den BemtEmail author
  • L.M. Geven
  • N.A. Kuitert
  • A. Risselada
  • J.R.B.J. Brouwers


Objective: The drug–drug interaction between oral anticoagulants (especially warfarin) and acetaminophen has been described, but evidence is conflicting and evidence for a similar interaction between acenocoumarol or phenprocoumon and acetaminophen is limited. Therefore, a study was performed to determine the influence of acetaminophen on oral anticoagulation with acenocoumarol or phenprocoumon in everyday practice.Method: Included were patients from two Dutch anticoagulant clinics who had used oral anticoagulants for at least three months and who started with acetaminophen (case group) or benzodiazepines (control group). Results: Fifty-four patients were included who had a first prescription of acetaminophen in their pharmacy record (during oral anticoagulant use) and twenty patients with a first prescription of a benzodiazepine (during oral anticoagulant use). The INR (International Normalized Ratio) difference before and after acetaminophen use was not statistically significant between the two groups and showed no dose dependency.Conclusion: These data do not demonstrate that acetaminophen, in the dosages used in everyday practice, has a clinically relevant influence on the INR in patients using acenocoumarol or phenprocoumon

Acenocoumarol Acetaminophen Drug-drug interaction Oral anticoagulation Paracetamol Phenprocoumon 


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Copyright information

© Kluwer Academic Publishers 2002

Authors and Affiliations

  • P.M.L.A. van den Bemt
    • 1
    Email author
  • L.M. Geven
    • 2
  • N.A. Kuitert
    • 3
  • A. Risselada
    • 3
  • J.R.B.J. Brouwers
    • 4
  1. 1.TweeSteden Hospital and St. Elisabeth HospitalTilburgThe Netherlands
  2. 2.Anticoagulant Clinic LeeuwardenThe Netherlands
  3. 3.Groningen University Institute for Drug Exploration (GUIDE)GroningenThe Netherlands
  4. 4.Groningen University Institute for Drug Exploration (GUIDE),Division of Pharmacoepidemiology and Drug PolicyState University of GroningenThe Netherlands

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