Compared efficacy and tolerance of the neuromuscular blockade induced by brand-name (Nimbex®) and generic (Cisatrex®) of cisatracurium in mechanically ventilated critically ill patients: a crossover double-blind randomized study

INTRODUCTION: use of generic drugs is common. However, there is still concern among patients and physicians that brand name drugs are more efficient. The aim of the study was to compare efficacy and tolerance between two forms of cisatracurium: brand name versus generic name. METHODS: it´s a crossover, randomized, double-blind physiological trial. Patients admitted for hypoxemic acute respiratory failure with PaO2/FIO2 < 200mmHg despite optimized ventilation and sedation thus requiring non-depolarizing neuromuscular blocking agents (NMBAs), were enrolled. Patients received consecutively, in a random order, cisatracurium brand name (Nimbex®) and generic (Cisatrex®) over two-hour period separated by one-hour washout period. Neuromuscular function was monitored by a calibrated train-of-four (TOF) stimulation device. Paralysis time delay to reach TOF of 2/4, recovery kinetics and tolerance were monitored. The number needed to demonstrate a significant difference in time delays to reach a TOF of 2/4 between the two forms of cisatracurium was estimated at 22 patients. RESULTS: twenty-two patients were included. Eight (36.4%) had acute respiratory distress syndrome; 8(36.4%), acute exacerbation of chronic obstructive pulmonary disease and 3(13.6%), status asthmaticus. Median [IQR] SAPS II at admission, 28.5 [22, 41]. PaO2/FIO2, 121 [81, 156] mmHg. Paralysis time delays were respectively, 80 [50, 112] vs. 87 [65, 115] minutes, in Nimbex® group and Cisatrex® group; (p=0.579). Within the recovery period, the between two-studied drugs´ difference in TOF was at 0.25±0.96; p=0.64. There were no significant hemodynamic differences. CONCLUSION: the present study revealed no significant differences in efficacy nor in tolerance between cisatracurium brand name Nimbex® and generic name Cisatrex® in hypoxemic ventilated patients.