Meloxicam Does Not Affect the Antiplatelet Effect of Aspirin in Healthy Male and Female Volunteers

This study determined if meloxicam, a selective cyclooxygenase (COX)‐2 inhibitor, interferes with the antiplatelet effect of aspirin using platelet aggregation and thromboxane (Tx) B 2 endpoints in healthy volunteers. Eight male and 8 female volunteers participated in this open‐label, randomized, two‐treatment, two‐way crossover trial. Treatment 1 was meloxicam (15 mg qd) over 4 days, and then aspirin (100 mg qd) was ingested 2 hours after meloxicam for an additional 7 days. Blood samples were taken 2, 6, and 24 hours after the last dose. Treatment 2 consisted of only aspirin (100 mg) over 2 days. Samples were taken at the same time points. Each subject received both treatments with a 2‐week washout between the treatment periods. Treatments were safe and well tolerated. The initial 4‐day treatment with meloxicam had no effect on platelet aggregation but reduced serum TxB 2 by 64% ± 19%. Addition of aspirin (100 mg qd) for 7 days resulted in complete inhibition of aggregation and TxB 2 for 24 hours. Two‐day treatment with only 100 mg aspirin also resulted in complete inhibition of platelet aggregation and TxB 2 . These results indicate that meloxicam does not affect the ability of aspirin to inhibit COX‐1 in platelets, thereby allowing aspirin to effectively prevent platelet aggregation and reduce TxB 2 levels, and that meloxicam is selective for COX‐2