A series of 3-(4-piperidinylthio)-1H-indoles was synthesized and evaluated in mice in the phenylbenzoquinone (PBQ)-induced writhing and hot plate tests. Most of these compounds are good analgesics with activities comparable to that of morphine. Among them compound 1i (UP 237-61), which has a strong serotonin binding profile, has an interesting antinociceptive activity which is not reversed by naloxone.
