A compound of formula: wherein X is S or O and A, R.sub.1, R.sub.2, R.sub.3, R.sub.4, n, and m are disclosed herein, or a pharmaceutically acceptable salt thereof (a "Pyridazinylpiperazine Compound"), compositions comprising a Pyridazinylpiperazine Compound, and methods for treating or preventing pain, UI, an ulcer, IBD and IBS in an animal comprising administering to an animal in need thereof an effective amount of a Pyridazinylpiperazine Compound are disclosed herein.