COMPARATIVE HEMODYNAMIC-ALTERATIONS INDUCED BY PIPECURONIUM AND PANCURONIUM

Haemodynamic effects of pipecuronium bromide (Pi.) and pancuronium bro mide (Pa.) were studied on isolated rabbit's heart, guinea pig's trach eal chain as well as the blood pressure in pentobarbital anaesthetized dogs. Pi. induced negative inotropic and chronotropic effects on the isolated rabbit's heart especially in lower concentrations. However, h igher concentrations provoked two opposite effects, negative chronotro pic and positive inotropic activity. In addition, Pa. in lower concent rations caused positive inotropic and negative chronotropic activity, while higher concentrations induced negative inotropic and chronotropi c activity. Cardioinhibitory actions of both tested drugs are not due to either cholinergic or beta1-adrenergic blocking effect but it may b e due to nicotine-like activity. In anaesthetized dogs, i. v. injectio ns of both tested drugs produced a tansient decrease in systolic and d iastolic pressure in doses above the therapeutic level. This effect ma y be referred to the partial ganglion blocking effect of both tested d rugs.