The international surgical journal with global reach

This is the Scientific Surgery Archive, which contains all randomized clinical trials in surgery that have been identified by searching the top 50 English language medical journal issues since January 1998. Compiled by Jonothan J. Earnshaw, former Editor-in-Chief, BJS

Combined effects of aspirin and the novel antiplatelet agent clopidogrel on platelet function in vivo and in vitro. BJS 2001; 88: 613-614.

Published: 6th December 2002

Authors: D. A. Payne, P. D. Hayes, P. R. Bell, A. H. Goodall, A. R. Naylor

Background

The platelet adenosine 5′‐diphosphate (ADP) receptor antagonist clopidogrel has proved an effective antiplatelet agent in the prevention of arterial thrombosis. In the vast majority of studies clopidogrel has been used as an alternative to aspirin, but the widespread use of aspirin, and the different modes of actions of the two drugs, makes it important to determine the safety and efficacy of using both drugs in combination. This study reports the effect of this drug combination on bleeding times and platelet function in humans.

Method

The study was conducted in normal, healthy subjects to evaluate the effects of different doses of clopidogrel on bleeding time, platelet aggregation and activation, above a baseline of standard aspirin therapy. Seven normal men (mean age 30 years) were given aspirin (150 mg) for 3 days. Subjects received clopidogrel (75 mg) at 24 and 48 h, followed by a third dose of clopidogrel (300 mg) on day 3.

Results












Baseline
Aspirin alone
Aspirin + low‐dose clopidogrel
Aspirin + high‐dose clopidogrel




Bleeding time (min)
5·1
7·5
17·5
24·9


Aggregation in response to ADP (%)
72
48
35
25


Fibrinogen binding in response to ADP (%)
64
50
40
24




Conclusion

Blocking both the cyclo‐oxygenase and ADP pathways of platelet activation has a profound effect on platelet response to agonists, which may offer significant potential benefit in preventing thrombotic events relative to aspirin alone. Achieving the correct balance between haemostasis and thrombosis with these useful agents will require further study. © 2001 British Journal of Surgery Society Ltd

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