[Reduction of the effects of indomethacin by aspirin. Value of measurement of the articular index and sigma ESR].

Two groups, A and B, were selected at random amongst a total of 31 patients suffering from chronic inflammatory rheumatic disorders. The patients in group A (n = 16) received succesively: Placebo (2d), Indomethacin (5d). Indomethacin + aspirin (5d). The order of the 5 day treatment periods was reversed for the patients in group b (n = 15). The daily dose of indomethacin was 150 mg. That of aspirin was 1500 mg. Four parameters were measured at the end of each period of treatment: total serum indomethacin, articular index (Ritchie), ESR (Westergren) and the sigma ESR - a new technique for the measurement of sedimentation rate. No conclusions could be drawn from the analysis of variations in ESR. Concordant and statistically significnat variations in articular index and the sigma ESR showed a reduction in the activity of indomethacin under the influence of aspirin. The inhibitory effect of aspirin. The inhibitory effect of aspirin continues after the drug stopped. This reduction in indomethacin activity is not related to a decrease in serum concentrations of the medication which are not significantly altered when aspirin is taken.