The invention thus provides the compounds of formula (I) ##STR00001## and pharmaceutically acceptable salts thereof, in which: R.sup.1 and R.sup.2 are independently selected from the group consisting of H, C.sub.1-6alkyl, C.sub.2-6alkenyl, C.sub.3-6alkynyl, C.sub.3-10cycloalkylC.sub.0-6alkyl and C.sub.4-12bridged cycloalkyl; R.sup.3 is selected from the group consisting of C.sub.1-6alkyl, NH.sub.2 and R.sup.5CONH; R.sup.4 is selected from the group consisting of CH.sub.2F, CHF.sub.2, CF.sub.3CH.sub.2, CF.sub.3CHF and CF.sub.3CF.sub.2; and R.sup.5 is selected from the group consisting of H, C.sub.1-6alkyl, C.sub.1-6alkoxy, C.sub.1-6alkylOC.sub.1-6alkyl, phenyl, HO.sub.2CC.sub.1-6alkyl, C.sub.1-6alkylOCOC.sub.1-6alkyl, C.sub.1-6alkylOCO, H.sub.2NC.sub.1-6alkyl, C.sub.1-6alkylOCONHC.sub.1-6alkyl and C.sub.1-6alkylCONHC.sub.1-6alkyl.Compounds of formula (I) are potent and selective inhibitors of COX-2 and are of use in the treatment of the pain, fever, inflammation of a variety of conditions and diseases.