Butorphanol: A kappa agonist revisited

Abstract

Most opioids were developed in the search for drugs that were selective analgesics, antidiarrheals or cough suppressants that lacked the reinforcing, physical dependence and respiratory depressant capacities of morphine-like drugs. Pharmacologic assessment of these drugs in addict volunteers led to the idea of multiple receptors (mu and kappa) to explain the differing profiles of agonist effects. One result was the development and therapeutic introduction in 1978 of a parenteral preparation of the kappa agonist butorphanol as an opioid analgesic of low abuse potential. In 1992, the introduction of a transnasalppreparation of butor phanol into the USA led to an increased therapeutic use of butorphanol. This increased use led us to review the current pharmacologic and epidemiologic evidence on the abuse potential of a prototype for kappa agonists. Our aim was to reevaluate the idea that the public health and social problems that accompany the therapeutic use of morphine like drugs would not accompany the therapeutic use of kappa agonists such as butorphanol.