Evidence map›Paper›PMID 41186801›Full record

ArticleDrug safety2026

A National Response to Warfarin Shortages: Evaluating Regulatory Substitution and Notified Shortages and Their Effects on Antithrombotic Dispensings, Pathology Monitoring and Adverse Event Trends in Australia.

Roua Azroun, Lisa Kalisch Ellett, Nicole Pratt, Michael Ward, Jack Janetzki

Abstract read
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Article in Drug safety, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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0citing papers in PubMed
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1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

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3 · Its place in the literature

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No citing paper in PubMed yet.

4 · The record

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5 · Who and what money

Authors and funding

5 authors.

Roua AzrounClinical and Health Sciences, University of South Australia, GPO Box 2471, Adelaide, SA, 5001, Australia.ORCID http://orcid.org/0009-0000-8491-4886
Lisa Kalisch EllettClinical and Health Sciences, University of South Australia, GPO Box 2471, Adelaide, SA, 5001, Australia.ORCID http://orcid.org/0000-0001-5063-6128
Nicole PrattClinical and Health Sciences, University of South Australia, GPO Box 2471, Adelaide, SA, 5001, Australia.ORCID http://orcid.org/0000-0001-8730-8910
Michael WardClinical and Health Sciences, University of South Australia, GPO Box 2471, Adelaide, SA, 5001, Australia.ORCID http://orcid.org/0000-0001-5121-5827
Jack JanetzkiClinical and Health Sciences, University of South Australia, GPO Box 2471, Adelaide, SA, 5001, Australia. Jack.Janetzki@unisa.edu.au.ORCID http://orcid.org/0000-0002-4171-3504

Funding

University of South Australia Summer Vacation Research Scholarship
6 · The paper itself

Abstract

backgroundMedicine shortages are an increasing threat to medicine safety and access. In Australia, a 7-month shortage of Coumadin 5-mg tablets (Dec 2022-Jul 2023) prompted Therapeutic Goods Administration (TGA) intervention via the Serious Scarcity Substitution Instrument (SSSI), allowing pharmacists to substitute 5-mg warfarin tablets with lower-strength tablets. Understanding the impact of this shortage on anticoagulant use and safety is essential for informing future regulatory responses.

aimsThe aim of this study was to assess the impact of the 2023 warfarin shortage in Australia on dispensing of warfarin and direct oral anticoagulants (DOACs), International Normalised Ratio (INR) testing, and adverse event reporting.

methodsMonthly national dispensing data (January 2020-August 2024) were obtained from Pharmaceutical Benefits Scheme (PBS) Date of Supply data. INR pathology data were sourced from Services Australia. The TGA Medicines Shortages Database identified relevant shortage periods. Warfarin-related adverse events were extracted from the TGA Database of Adverse Event Notifications. Interrupted time series assessed changes in dispensing and INR testing trends over time.

resultsWarfarin dispensing declined by 1094 prescriptions per month prior to March 2023 (p < 0.0001). A short-term increase occurred in March 2023 (+ 8625 prescriptions; p = 0.0017) following implementation of the SSSI, although this was not sustained. At the warfarin strength level, dispensing rose for warfarin 1 mg and 2 mg but fell for 5 mg, with subsequent compensatory increases; 3 mg remained stable. DOAC dispensing increased steadily before March 2023 (+ 3771 prescriptions per month; p < 0.0001) but declined thereafter (- 3056 per month; p < 0.0001), most notably for rivaroxaban and dabigatran, while apixaban decreased non-significantly. INR testing briefly increased during the shortage and SSSI. A modest rise in haemorrhage-related adverse events was observed.

conclusionWarfarin supply was maintained during the 2023 shortage through strength-based substitution under the SSSI, with limited impact on DOAC dispensing.

Indexed as

AnticoagulantsFibrinolytic AgentsWarfarinAdverse Drug Reaction Reporting SystemsAustraliaHumansInternational Normalized RatioAnticoagulantsFibrinolytic AgentsWarfarin

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.