ABSTRACT
Mivacurium, in a dose of 0.2 mg / kg body weight, produced a transient decrease in blood pressure [BP] and a transient increase in heart rate [HR] in anaesthetized cats. Mivacurium antagonized the hypotensive effect of acetylcholine [Ach] on PB and also antagonized the negative inotropic and chronotropic effects of Ach on isolated rabbit's heart. Meanwhile, mivacurium potentiated the hypertensive effect of adrenaline on BP and also the positive inotropic and chronotropic effects of adrenaline on isolated rabbit's heart. A clinical study was performed on forty adult surgical patients who received 0.2 mg / kg body weight mivacurium as a loading fast dose, then neuromuscular blockade was maintained either by a bolus dose of 0.06 mg / kg body weight in 20 patients, or by continuous infusion of 4 - 8 micro g / kg /min in another group of 20 patients whenever T1 returned. There was a brief transient decrease in the mean arterial pressure [MAP] and an increase in HR lasting for 1-3 minutes, but there was no significant change in MAP or HR after the second bolus dose or continuous infusion. The hemodynamic changes with mivacurium suggested histamine release. To conclude, mivacurium can be considered a safe drug in absence of clinically significant alterations in HR and MAP from baseline