A compound of formula:
##STR1##
(wherein X is O or S and R1, R3, R4, and
R5 are disclosed herein) or a pharmaceutically acceptable salt thereof
(a "Thiadiazolylpiperazine Compound"), pharmaceutical compositions comprising a
Thiadiazolylpiperazine Compound, and methods for treating or preventing pain in
a patient comprising administering to a patient in need thereof an effective amount
of a Thiadiazolylpiperazine Compound are disclosed.
