Negative reinforcing properties of naloxone in the non-dependent rhesus monkey: influence on reinforcing properties of codeine, tilidine, buprenorphine, and pentazocine.

Scheduled infusions of naloxone (1-100 micrograms/kg/inf.) and of buprenorphine (250 micrograms/kg/inf.) generated drug avoidance behavior in the non-dependent rhesus monkey under a continuous avoidance-escape paradigm. Pentazocine (1-100 micrograms/kg/inf.) codeine, (1-100 micrograms/kg/inf. and tilidine (1-250 micrograms/kg/inf.) were ineffective. Addition of varying doses of naloxone to scheduled infusions of codeine, tilidine, and pentazocine generated avoidance behavior not present with scheduled infusions of these opioids alone. The naloxone doses necessary for generation of avoidance behavior were low with the agonists codeine and tilidine, higher with the weak antagonist pentazocine, and highest with the strong antagonist buprenorphine. When monkeys were presented with the fixed tilidine-naloxone combination (100 + 8 parts) and pentazocine-naloxone combination (100 + 1 part) and the buprenorphine-naloxone combination (100 + 66 parts) presently in clinical use only the tilidine-naloxone combination generated drug avoidance behavior to an appreciable extent.