This invention relates to local epidural or intraspinal use of compounds of the formula: ##STR1## where X is H or CH.sub.3 and R.sub.1 and R.sub.2, which can be the same or different, are each H or CH.sub.3 and their stereoisomers and their non-toxic, pharmaceutically acceptable salts. Especially useful are the compounds known under the generic names medetomidine ((.+-.)-4-[1-(2,3-dimethylphenyl)ethyl]-1H-imidazole), dexmedetomidine (+)-4-[1-(2,3-dimethylphenyl)ethyl]-1H-imidazole and detomidine 4-(2,3-dimethylbenzyl)-1H-imidazole.
