Unbound plasma salicylate concentration in rheumatoid arthritis patients

This study was designed to investigate the relationship of free plasma salicylate to total plasma salicylate and to determine the clinical utility of monitoring the free plasma salicylate concentration. Analysis of 46 patient samples indicated a close correlation between the free and total plasma concentration and that there is no additional advantage to monitoring the free plasma salicylate concentration. Also this study re-emphasizes the unique pharmacokinetic characteristics of salicylate, whereby the amount of free plasma salicylate increases disproportionately with increased total plasma salicylate concentration.