Gastrointestinal Blood Loss of Oxaprozin and Aspirin with Placebo Control

Abstract

The objective of this study was to compare the effects of oxaprozin (4,5‐diphenyl‐2‐oxazolepropionic acid), a nonsteroidal, antiinflammatory compound, and aspirin in a double‐blind, placebo‐controlled study to estimate gastrointestinal bleeding. The determination of fecal blood loss was made quantitatively by the use of the radioactive (⁵¹Cr) technique. During the first week, subjects were controlled with and without placebo. At the end of the second week, the subjects were divided and randomly assigned to one of three groups; 10 received 1200 mg oxaprozin (600 mg twice daily), 11 received 3900 mg aspirin (975 mg four times a day), and the remaining 8 subjects received placebo for two weeks. During the last two weeks, all received placebo again. A statistical analysis of variance showed that there were no statistical differences between the groups during the first and last two weeks of placebo therapy. During the active treatment period, weeks 3 and 4, there were statistically significant differences among the three groups. The mean blood loss during week 3 was significantly greater for the aspirin group, 8.8 ml/day, than the oxaprozin group, 3.3 ml/day (P < 0.05), and the placebo group, 1.4 ml/day (P < 0.001). The smaller difference between oxaprozin and placebo was also significant (P < 0.05). During the fourth week, the mean daily blood loss among oxaprozin patients had decreased to 2.3 ml/day, and no statistically significant difference from placebo (1.1 ml/day) was found.