Case reports suggest that most 
NSAIDs can occasionally enhance the effects of 
warfarin and other coumarins (acenocoumarol, phenprocoumon), resulting in increased anticoagulant effects and sometimes severe bleeding events.    
   Monitor the anticoagulant effect if 
NSAIDs are added to or withdrawn from the treatment of patients taking anticoagulants. Note that since 
NSAIDs reduce platelet aggregation and cause 
gastrointestinal irritation they can prolong and worsen any bleeding events.