SAT0057 A double-blind, placebo-controlled study to evaluate the effects of valdecoxib, a novel cox-2 specific inhibitor, on platelet function in the elderly

Abstract

Background Valdecoxib is a novel oral COX-2 specific inhibitor. COX-2 specific inhibitors effectively treat pain and inflammation without causing many of the side effects commonly associated with conventional NSAIDs. Objectives The purpose of this study was to compare the effects of valdecoxib to ibuprofen on platelet function in healthy subjects, > = 65 years of age. Methods In this single-centre, double-blind, placebo-controlled, parallel-group study, 65 healthy adults, aged 65–95 years, were randomised to receive valdecoxib 40 mg BID, ibuprofen 800 mg TID, or placebo for 7.5 days. Platelet aggregation in response to arachidonate (AA), adenosine diphosphate (ADP), or collagen; serum thromboxane B 2 (TxB 2 ) concentrations; and Simplate II bleeding times were assessed at 2, 4, and 8 h after dosing on Days 1 and 8. Vital signs and adverse events were monitored throughout the study. Results Platelet aggregation responses to AA, collagen, and ADP were not affected by treatment with valdecoxib 40 mg BID. In contrast, ibuprofen resulted in marked decreases in AA-induced platelet aggregation at the 2 h and 4 h assessments on Days 1 and 8. The effects of ibuprofen on platelet aggregation in response to collagen and ADP were not as great as seen with AA. However, for all three stimuli, ibuprofen demonstrated significantly greater decreases in platelet aggregation compared to placebo and valdecoxib at several time points. Valdecoxib 40 mg BID had no effect on bleeding times or serum TxB 2 concentrations compared to placebo. Bleeding times were significantly prolonged (p 2 concentrations significantly reduced (p Conclusion Valdecoxib 40 mg BID does not affect platelet function, serum TxB 2 levels or bleeding times, and is well tolerated in healthy elderly subjects. However, ibuprofen significantly alters hemostasis. These findings suggest that valdecoxib can provide its previously demonstrated analgesic and anti-inflammatory therapeutic benefits without negatively influencing platelet function in subjects > = 65 years. Sponsored by Pharmacia Corporation and Pfizer, Inc.