(R)- enantiomer does not exhibit COX inhibition – it was > 100-fold less active than (S)- enantiomer on both COX subtypes. (R)- enantiomer is about 60 times less potent than the (-)-S isomer in the carrageenan edema test and ca. 230 times less active than the (-)-S isomer in the mouse phenylquinone writhing assay. R-ketorolac is an inhibitor of fatty acid amide hydrolase, but not at physiological concentrations.