Effects of pentazocine and tripelennamine on analgesia.

The analgesic effects of pentazocine and tripelennamine, alone and in combination, were assessed in rats with a hot plate apparatus. In Experiment 1, the combination of tripelennamine with chronic pentazocine produced analgesia at doses which were not analgesic when the drugs were given alone. This combination also reestablished analgesia in subjects made tolerant to pentazocine's effects. In Experiment 2, development of tolerance to the analgesic effects of pentazocine was delayed by addition of tripelennamine. These data may contribute to a rationale for the current popularity of combined pentazocine and tripelennamine abuse.