Pentazocine-tripelennamine ("T's and Blues") substitution studies in morphine-dependent rodents

Tripelennamine, pentazocine and various pentazocine-tripelennamine combinations were tested for their ability to substitute for morphine in morphine-dependent rodents. Rats and mice were rendered physically dependent on morphine by the Drug-Admixed Food Method. Pentazocine produced a dose-related partial suppression of morphine withdrawal signs in mice, as well as in both mildly and severely dependent rats. Tripelennamine did not suppress morphine withdrawal signs, but rather aggravated them. Furthermore, tripelennamine did not potentiate the ability of pentazocine to suppress morphine withdrawal signs. It is concluded that the primary reason for the reported "street" abuse of the tripelennamine-pentazocine combinations is not related to any remarkable ability of the combination to effectively suppress the discomfort of heroin withdrawal.