This invention is directed to a method for preventing or treating neuropathic pain and cluster and migraine headache-associated pain comprising administering to a subject in need thereof a therapeutically effective amount of a compound of Formula (I): ##STR00001## wherein phenyl is substituted at X with one to five halogen atoms independently selected from the group consisting of fluorine, chlorine, bromine and iodine; and; R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are independently selected from the group consisting of hydrogen and C.sub.1 C.sub.4 alkyl; wherein C.sub.1 C.sub.4 alkyl is optionally substituted with phenyl (wherein phenyl is optionally substituted with substituents independently selected from the group consisting of hydrogen, halogen, C.sub.1 C.sub.4 alkyl, C.sub.1 C.sub.4 alkoxy, amino, nitro and cyano).