Abstract
Objective: To assess the celecoxib interference with the anti-platelet effect of low dose aspirin.
Methodology: We selected eighteen healthy volunteers, aged between 22 and 50 years and allocated them into three groups. After written informed consent the three groups (A,B and C) were given aspirin (10mg once a day), celecoxib (200mg twice a day) and both aspirin and celecoxib each. The drugs were administered for six consecutive days, prohibiting the concomitant use of any other drug. We obtained blood samples from the study subjects on two occasions, before starting drugs and then on the seventh day and analyzed them for platelet aggregation (ADP and collagen induced) and serum thromboxane A2 levels.
Results: If 150mg aspirin is taken daily along with twice daily doses of celecoxib (200mg), aspirin continues to exert an antiplatelet effect. Results show that mean platelet aggregation with ADP was reduced to 60.00±6.19 percent from a baseline value of 83.33±4.77 percent. When collagen was used as a reagent the aggregation of platelets was markedly reduced to 34.50±7.71 from a baseline of 79.17±5.83 percent. Similarly, mean thromboxane B2 levels reduced markedly from 854.88±51.18pg/ml to 539.94±86.84 pg/ml.
Conclusion: It is safe to use celecoxib with aspirin, as the anti-platelet effect of the latter is not attenuated.

Key words: Non-steroidal anti-inflammatory drugs, aspirin, celecoxib.