following discrimination training , the morphine stimulus was generalized to propoxyphene , methadone , fentanyl , and sulfentanyl in a dose-dependent manner , and saline was generalized to alcohol , pentobarbital , azaperone , clonidine , naloxone , and p-chloroamphetamine . p-chloroamphetamine failed to block the morphine stimulus .
C0015846
fentanyl
C0143993
sulfentanyl