ABSTRACT
The existence of a severe toxic interaction from the clinical use of pethidine and monoamine oxidase [MAO] inhibitors is well known. The present study evaluates the possibility of such an interaction for the opioid partial agonist Nalbuphine and the pure agonist fentanyl. Conscious rabbits [n = 6] in each group pretreated 24 hours previously with physiological saline or the MAO inhibitor tranylcypromine [Parnate] 1.5 mg/kg S.C. were subsequently given physiological saline, pethidine 5 mg/kg, fentanyl 0.02 mg/kg and effect and parnate produced only a small increase in the rabbits temperature, the combination of parnate and pethidine produced a marked hyperpyrexia [+ 4.4 +/- 0.19°C, P < 0.001], hypertension 33.9 +/- 3.1 mmHg; P < 0.01] and agitation. Two rabbits died at 40 and 50 minutes after the pethidine- parnate combination. Nalbuphine and fentanyl were without significant effects on the parameters when given after the MAO-inhibitor parnate