Diclofenac antiplatelet effect

A number of pharmacodynamic studies have investigated whether or not NSAIDs affect the antiplatelet effects of aspirin. Celecoxib 200 mg twice daily, diclofenac 75 mg twice dailyetoricoxib 120 mg daily, lumira-coxib 400 mg daily, meloxicam 15 mg dailynaproxen 500 mg twice daily, parecoxib 40 mg twice dailyand rofecoxib 25 mg daily have all been shown not to alter the antiplatelet effects of aspirin in doses of 75 to 325 mg daily. The effects of ibuprofen ate less elear, and may be related to the order of drug administration. 

The evidence currently available on the antagonism of antiplatelet effects is insufficient to recommend that ibuprofen is not used with low-dose aspirin. Nevertheless, some have concluded that when patients taking low-dose aspirin for cardioprotection require long-term NSAIDs for inflammatory conditions, the use of diclofenac or naproxen would seem preferable to ibuprofen.A coxib was also suggested as an alternative,but the subsequent suggestion of an increased risk of serious cardiovascular effects with the coxibs (as a class ) probably precludes this. Recently the Commission on Human Medicines (CHM) in the UK has advised that there may be a small increased risk of thrombotic events with the non-selective NSAIDs, particularly when used at high doses and for long-term treatment. ... 

Paracetamol levels are increased by diflunisal. Aspirin, diclofenac, nabumetone and sulindac pharmacokinetics do not appear to be affected by paracetamol. There is no pharmacokinetic interaction between ibuprofen and paracetamol. Propacetamol, and possibly paracetamol, increase the antiplatelet effects of diclofenac, although the evidence is limited and the clinical relevance of this is uncertain. 

Celecoxib is currently indicated for the relief of signs and symptoms of osteoarthritis and rheumatoid arthritis and to reduce the number of adenomatous colorectal polyps in familial adenomatous polyposis as an adjunct to usual care. Celecoxib is at least as effective as naproxen in the symptomatic management of osteoarthritis and at least as effective as naproxen and diclofenac in the symptomatic treatment of rheumatoid arthritis, and it is less likely to cause adverse Gl effects. Celecoxib appears to be effective in the management of pain associated with both of these arthritic conditions, but effectiveness in acute or chronic pain has not been fully demonstrated. Unlike aspirin, celecoxib does not exhibit antiplatelet activity. Concomitant administration of aspirin and celecoxib may increase the incidence of Gl side effects. Another notable potential drug interaction with celecoxib is its ability, like other NSAIDs, to reduce the blood pressure response to angiotensin-converting enzyme inhibitors. A more detailed discussion of the chemical, pharmacological, pharmacokinetic, and clinical aspects of celecoxib is available (81). 

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