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Letter to the editor

Editor, – We read with interest the article 'Warfarin, antiplatelet drugs and their interactions' (Aust Prescr 2002;25:81-5) and were disappointed that although the authors emphasise the risks of combining warfarin with aspirin, they fail to acknowledge the proven benefits of this combination in patients with prosthetic heart valves. A recent meta-analysis1 showed that compared with anticoagulation alone, the addition of an antiplatelet drug reduced the risk of not only thromboembolic events (odds ratio 0.41, p < 0.001)but also total mortality (odds ratio 0.49, p < 0.001).

The old view that the combination is dangerous is still held by many doctors and pharmacists. We certainly agree with the authors' recommendation that with the combination, low-dose aspirin should be used and the INR 'kept at the lower end of the desired target', and that patients on the combination should be carefully monitored for possible bleeding complications, including gastrointestinal blood loss. However, the evidence that adding low-dose aspirin to warfarin reduces total mortality by 50% in these patients should not be ignored and needs wide dissemination.

Con Aroney
Associate Professor of Medicine
University of Queensland
Cardiology Department
Prince Charles Hospital
Brisbane

Peter Thompson
Professor of Medicine and Public Health
University of Western Australia
Perth

References

  1. Massel D, Little SH. Risks and benefits of adding anti-platelet therapy to warfarin among patients with prosthetic heart valves: a meta-analysis. J Am Coll Cardiol 2001;37:569-78.