Does butorphanol produce interaction with monoamine oxidase inhibitors [tranylcypromine]? comparative experimental study with pethidine

ABSTRACT

This study demonstrated the possibility of the interaction between tranylcypromine and butorphanol compared with pethidine. The LD50 of pethidine and butorphanol were determined in mice pretreated either with nonselective monoamine oxidase [MAO] inhibitors, tranylcypromine orally for eight days or with saline orally. Tranylcypromine decreased the LD50 of both pethidine and butorphanol by 70% and 41%, respectively. Anesthetized rabbits with halothane pretreated either with tranylcypromine or saline were given pethidine 5 mg/kg iv or butorphanol 0.5, 1 and 2 mg/kg iv, pethidine produced a marked increase in blood pressure in rabbits pretreated with tranylcypromine and did not affect significantly the heart rate. However, butorphanol did not affect either blood pressure or heart rate at dose of 0.5 or 1 mg/kg, but the largest dose of butorphanol [2mg/kg] produced hypotension and tachycardia in rabbits pretreated with tranylcypromine. Neither pethidine nor butorphanol affected the temperature of anesthetized rabbits pretreated with tranylcypromine or saline