Recommendations for warfarin in Victorian public hospitals

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Editor, – There are currently two brands of warfarin available in Australia (Marevan and Coumadin), both manufactured by the Boots Company. These brands have not been demonstrated to be bioequivalent.¹ There is no clinical justification for both products, and availability contributes to potential medication errors and confusion for patients and carers.^2,3,4

The problem has been considered by the Melbourne Teaching Hospitals' Drug Usage Group (MTHDUG). This consists of 11 member hospitals and 19 associate member hospitals and is an affiliate of the Victorian Drug Usage Advisory Committee.

MTHDUG approached the manufacturer in early 2001 suggesting that consideration be given to phasing out one of the brands, however it has been reluctant to do so. Consequently, MTHDUG after communication and feedback from key stakeholders with an interest in the monitoring and prescribing of warfarin has made the following recommendations:

1. that Coumadin, the more widely used brand, be the primary brand of warfarin to be stocked and prescribed in Victorian hospitals;

2. that Marevan will be supplied only if specifically requested for a particular patient.

The impact of this strategy will be limited initially to patients commencing warfarin therapy in public hospitals. It is hoped that other institutions and individual doctors who also start warfarin therapy will also consider only prescribing Coumadin. Substitution of Coumadin in patients whose INR is stable on Marevan will require close monitoring.

MTHDUG is notifying community pharmacists and general practitioners about the recommendations through a range of professional forums and publications. Assessment of the impact of these recommendations will be ongoing.

Michael Dooley
Chairman
Melbourne Teaching Hospitals' Drug Usage Group
Carlton, Vic.