Effect of Diclofenac Sodium on Aspirin’s Antithrombotic Role

Abstract

Objective: To assess whether diclofenac sodium interferes with the anti-platelet effect of low dose aspirin. Study Design: Quasi- experimental study. Place and Duration of Study: Department of Pharmacology and Therapeutics, Army Medical College and Armed Forces Institute of Pathology Rawalpindi. Material and Methods: Eighteen healthy volunteers, divided into three groups, between the ages of 22-50 years, after written informed consent were selected according to a set criterion. They were given aspirin (150mg) once a day and diclofenac sodium 50mg three times a day for six consecutive days while use of any other drug was prohibited. Blood samples were taken from the study subjects on two occasions, before starting drugs and then on the seventh day. Blood samples were analyzed for platelet aggregation (ADP and collagen induced) and serum thromboxane B2 levels. Results: When a single daily dose of 150mg aspirin is taken with three daily doses of diclofenac sodium (50mg), results show that the anti-platelet effect of aspirin still remains. The mean platelet aggregation with ADP was reduced to 55.83 ± 5.38 percent from a baseline value of 71.67 ± 5.27 percent. Similarly if collagen was used as a reagent the aggregation of platelets was markedly reduced to 40.83 ± 6.63 from a baseline of 66.67 ± 6.54 percent. Results showed a prominent inhibition of aggregation of 22.10% for ADP and 38.75% for collagen. Also, mean thromboxane B2 levels reduced markedly from 971.11 ± 128.91 pg/ml to 702.99 ± 101.59 pg/ml. Conclusion: It is safe to use diclofenac sodium with aspirin, as the anti-platelet effect of the latter is not attenuated. Keywords: Anti platelet, Aspirin, Diclofenac.