Frequency of Concurrent Use of Warfarin with Potentially Interacting Drugs

Wittkowsky, Ann K.; Boccuzzi, Stephen J.; Wogen, Jenifer; Wygant, Gail; Patel, Pankaj; Hauch, Ole

doi:10.1592/phco.24.17.1668.52338

Cited by 70 publications

(59 citation statements)

References 16 publications

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“…In many countries, warfarin is the coumarin of first choice. Potential drug interactions during anticoagulant therapy with warfarin have been shown to be a frequent issue, as well [8,9]. Among 134,833 patients receiving long-term warfarin therapy, 109,998 (81.6%) were prescribed a concurrent prescription for at least one PID [8].…”

Section: Discussionmentioning

confidence: 99%

Quantity and quality of potential drug interactions with coumarin anticoagulants in the Netherlands

2007

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Objective Coumarin anticoagulants are prone to potentially life-threatening drug-drug interactions due to a combination of unfavorable properties. However, real life data on the actual occurrence are scarce. The aim of this study was to quantify and qualify potential drug interactions with coumarin anticoagulants in daily practice. Methods A cohort study including all users of phenprocoumon or acenocoumarol during the period 1991-2003 in the PHARMO Record Linkage System. All 24 individual drugs and 11 drug groups interacting with coumarins according to central database used in the Dutch pharmacies were considered. Main outcome measure Frequency and type of potential drug interactions during anticoagulant therapy with coumarins. Results 48,627 out of 76,455 mainly acenocoumarol-users (64%) were dispensed at least one potentially interacting drug (PID) during anticoagulant therapy. About 35% of these cases were dispensed a (very) strongly interacting drug, whereas 3% were dispensed a contraindicated drug. Antibacterial drugs and NSAIDs (39% and 37% of all users, respectively) were the most frequently dispensed PIDs. Conclusion Potential drug interactions with coumarins frequently occur in daily practice, confronting two-thirds of patients with an increased risk of bleeding. To a large part, this is attributable to commonly prescribed medication like antibacterial drugs and NSAIDs. This situation substantiates the need for proper monitoring or new anticoagulants with less drug-drug interactions.

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Section: Discussionmentioning

confidence: 99%

Quantity and quality of potential drug interactions with coumarin anticoagulants in the Netherlands

2007

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“…17,39 In this study, the majority of DDIs were attributed to warfarin and other anticoagulants, a finding that is consistent with other studies of DDIs. 28,40 To further investigate whether the disproportionate representation of warfarin interactions might be associated with biased estimates, a multivariate analysis was performed with and without warfarin interactions (Tables 4 and 5). The results from the analyses were different; prescribers in the intervention group were significantly more likely to prescribe potentially interacting medications than the control group, when warfarin interactions (specifically with NSAIDs) were included.…”

Section: ■■ Conclusionmentioning

confidence: 99%

Effect of an Educational Outreach Program on Prescribing Potential Drug-Drug Interactions

Malone

Liberman

Sun

2013

JMCP

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BACKGROUND: The topic of improving prescribing practices is a major focus of many national initiatives, not only to enhance the quality of health care but also to reduce medical care costs. Educational outreach (also known as academic detailing) is a type of postgraduate education where trained clinical consultants meet face-to-face with prescribers to provide one-on-one information. Ideally, such visits promote evidence-based knowledge, create trusting relationships, and induce practice change, particularly with regard to prescribing potentially interacting medications.

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“…Observational studies indicate that antiplatelet and anticoagulant combinations, with concomitant use of non-steroidal anti-inflammatory drugs (NSAIDs), selective serotonin re-uptake inhibitors (SSRIs) or antibacterial drugs increase bleeding risk [11,[13][14][15][16][17]. Up to 80% of anticoagulant users are described as using potentially hazardous combinations of medicines [18,19]. Studies of anticoagulant-related bleeding events from spontaneous reporting systems also show frequent use of interacting medicines, but the types of interacting medicines have not been described in detail [1,3].…”

Section: Introductionmentioning

confidence: 99%

Warfarin‐associated bleeding events and concomitant use of potentially interacting medicines reported to the Norwegian spontaneous reporting system

Narum

Solhaug

Myhr

et al. 2011

Brit J Clinical Pharma

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WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT • Bleeding is the main adverse drug reaction of warfarin use. • Several medicines, herbal products and dietary supplements may interact with warfarin. • A high percentage of patients on warfarin receive potentially interacting substances. WHAT THIS STUDY ADDS • Potentially interacting medicines were used in more than 50% of the warfarin‐associated bleeding events reported to the Norwegian spontaneous reporting system. • Only a minority of the concomitant medicines were reported as suspected or interacting in the reporters' assessments. • There was a higher degree of under‐reporting of pharmacokinetically than of pharmacodynamically interacting medicines. AIMS To study warfarin associated bleeding events reported to the Norwegian spontaneous reporting system and evaluate the differences in assessment of potentially interacting medicines between reporters and evaluators. METHODS Data on bleeding events on warfarin were retrieved from the Norwegian spontaneous reporting system database. Key measurements were time to bleeding, use of concomitant medications and the evaluation done by reporters. RESULTS In 289 case reports a total of 1261 medicines (median 4.0 per patient, range 1–17) was used. The evaluators (authors of this article) identified 546 medicines including warfarin (median 2.0 per patient, range 1–7) that could possibly cause bleeding alone or in combination. Reporters assessed 349 medicines (median 1.0 per patient, range 1–4) as suspect. Evaluators identified 156 pharmacokinetic and 101 pharmacodynamic interactions, compared with 19 pharmacokinetic and 56 pharmacodynamic interactions reported as suspected by the reporters. Time to bleeding was stated in 224 reports. Among the early bleeding events, the reports on warfarin without interacting medicines showed the highest INR (international normalized ratio). Heparin was used in 17/21 reported bleeding events during the first week on warfarin. Among the late bleeding events, reports with pharmacokinetic interacting medicines had the highest INR. CONCLUSIONS Concomitant use of potentially interacting medicines was involved in the majority of the warfarin‐associated bleeding events reported to the Norwegian spontaneous reporting system. Reporters assessed mostly warfarin as the only contributor to bleeding. In particular, pharmacokinetically interacting medicines were not suspected as contributing to bleeding.

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Frequency of Concurrent Use of Warfarin with Potentially Interacting Drugs

Cited by 70 publications

References 16 publications

Quantity and quality of potential drug interactions with coumarin anticoagulants in the Netherlands

Quantity and quality of potential drug interactions with coumarin anticoagulants in the Netherlands

Effect of an Educational Outreach Program on Prescribing Potential Drug-Drug Interactions

Warfarin‐associated bleeding events and concomitant use of potentially interacting medicines reported to the Norwegian spontaneous reporting system

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