- Authors:
- DOI:
- 10.1002/pds.3714
- Abstract:
- PurposeWe present a database of prescription drugs and international normalized ratio (INR) data and the applied methodology for its use to assess drug-drug interactions with vitamin K antagonists (VKAs). We use the putative interaction between VKAs and tramadol as a case study. MethodsWe used a self-controlled case series to estimate the incidence rate ratio (IRR) comparing the rate of INR measurements of 4.0 in concomitant tramadol and VKA-exposed periods to VKA-only-exposed periods. Secondary analyses considered specific subgroups, alternative exposure criteria, alternative outcome definitions, and other drugs. ResultsWe identified 513 VKA users with at least 1 INR measurement 4.0 and concomitant tramadol and VKA exposure during the observation period. The overall IRR was 1.80 (95% confidence interval [CI], 1.53-2.10), with a stronger association among users of phenprocoumon compared to warfarin (IRR, 3.37; 95%CI, 2.50-4.53 and IRR, 1.46; 95%CI, 1.20-1.76, respectively). We observed larger IRRs with stricter outcome definitions. Concomitant tramadol and VKA exposure was also associated with an increased rate of low INR measurements (i.e.,
- Type:
- Journal article
- Language:
- English
- Published in:
- Pharmacoepidemiology and Drug Safety, 2014, Vol 23, Issue 11, p. 1160-1167
- Main Research Area:
- Medical science
- Publication Status:
- Published
- Review type:
- Peer Review
- Submission year:
- 2014
- Scientific Level:
- Scientific
- ID:
- 272591301
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