Influence Of Combined Therapy Of Selective Cyclooxygenase2-inhibitor Meloxicam And Low-dose Aspirin On Prostacyclin-thromboxaneA₂ Balance Of Cardiovascular Patients

Objective: The balance between biosynthesis of prostacyclin and that of thromboxane A2 has been proved to be important in the prevention of thrombosis. The present study was to investigate the influence of combined therapy of selective cyclooxygenase-2 inhibitor meloxicam and low-dose aspirin on prostacyclin-thromboxaneA2 balance of cardiovascular patients. Methods: Twenty hypertensive patients with or without coronary heart disease were randomly divided into 2 groups. One was combined-therapy group whose members received enteric-coated aspirin 75mg/d for 11 days. The other was single-therapy group whose members received enteric-coated aspirin 75mg/d for 7 days and enteric-coated aspirin 75mg/d and meloxicam 7.5mg/d for the next 4 days. The metabolic products of prostacyclin and thromboxaneA2 (6-keto-prostaglandinF1α and thromboxaneB2 respectively) were determined by radioimmunoassay of patients' fast blood on the eighthand the twelfth morning. Platelet aggregation was also measured. Results: (l)There was a trend toward lower ratio of serum 6-keto-prostaglandinF1. to thromboxaneB2 after combined therapy of aspirin and meloxicam whereas there was no such trend in the single-therapy group (P=0.056 and 0.799 respectively). (2)The ratio of patients' with coronary heart disease in the combined-therapy group decreased significantly after combined therapy (P=0.027), while patients with coronary heart disease in the single-therapy group had no significant change in the ratio (P>0.05). (3)The decreasing amplitude of the ratio of patients' with coronary heart disease in the combined-therapy group was significantly greater than that in the single-therapy group (P<0.05). (4) The two groups had no significant difference hi 6-keto-prostaglandinF1α, thromboxaneB2, maximal platelet aggregation rate and aggregation slope on the eighth morning and on the twelfth morning (P>0.05).Conclusion: Combined therapy of selective cyclooxygenase-2 inhibitor meloxicam (7.5mg/d) and aspirin (75mg/d) in cardiovascular patients, especially in patients with coronary heart disease, lowered the ratio of serum 6-keto-prostaglandinFi. to thromboxaneB2, which indicates that the prostacyclin-thromboxaneA2 balance was shifted toward a more prothrombotic direction.