Warfarin remains drug of choice in stroke prevention
Oral anticoagulants, such as warfarin, are superior to aspirin plus clopidogrel in the prevention of stroke for patients with atrial fibrillation (AF), according to the results of a study published last week in The
Lancet (2006;367:1903).
Because of the variability of patient response to warfarin and the increased
risk of bleeding, investigators aimed to assess whether an intensive
antiplatelet regimen would be an equally effective alternative for the
prevention of stroke in AF. They randomised 6,706 patients with AF to
receive either an oral anticoagulant or a combination of aspirin and
clopidogrel.
The annual risk of primary events (stroke, non central nervous system
embolus, myocardial infarction and vascular death) was 5.60 per cent
in the aspirin/clopidogrel group compared with 3.93 per cent in the oral
anticoagulant group (relative risk 1.44, 95 per cent confidence interval
1.18–1.76; P=0.0003).
Stroke (ischaemic and haemorrhagic stroke combined) was also more likely
in the aspirin/clopidogrel group (1.72, CI 1.24–2.37; P=0.001).
The authors found that oral anticoagulation was especially superior in
the subgroup of patients who were already taking this medicine before
the trial started (some 77 per cent of patients). Accordingly, they suggest
that because of the large number of patients who were taking oral anticoagulants
before the study began — and the possible advantage that being
stabilised on the treatment may have conferred — the study does
not clearly define the benefit of oral anticoagulation over aspirin/clopidogrel
for patients who have never taken either treatment. |
The
Pharmaceutical Journal
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