A compound of formula: where Ar.sub.1, Ar.sub.2, X, R.sub.3, and m are as disclosed herein or a pharmaceutically acceptable salt thereof (a "Tetrahydropiperidyl Compound"); compositions comprising an effective amount of a Tetrahydropiperidyl Compound; and methods for treating or preventing pain, UI, an ulcer, IBD, IBS, an addictive disorder, Parkinson's disease, parkinsonism, anxiety, epilepsy, stroke, a seizure, a pruritic condition, psychosis, a cognitive disorder, a memory deficit, restricted brain function, Huntington's chorea, amyotrophic lateral sclerosis, dementia, retinopathy, a muscle spasm, a migraine, vomiting, dyskinesia, or depression in an animal comprising administering to an animal in need thereof an effective amount of a Tetrahydropiperidyl Compound are disclosed herein.