An equal number of randomised studies have found a modest increase in the anticoagulant effect (e.g. an increase in INR of 1) of coumarins as have reported no effect. There are isolated case reports of an increase in anticoagulant effects in patients taking
warfarin or acenocoumarol and
paracetamol.
On the basis of the available data, it is not possible to firmly recommend increased monitoring, or dismiss its advisability. Further study is clearly needed. Para- cetamol is still considered to be safer than aspirin or NSAIDs as an analgesic in the presence of an anticoagulant because it does not affect
platelets or cause gastric bleeding.