The optimal priming dose for atracurium

Abstract

To determine the optimal priming dose for administration in divided doses, atracurium was given to 77 patients either in a single dose of 0.5 mg X kg-1 or in an initial dose of 0.04, 0.05, 0.06, 0.07, 0.08 or 0.09 mg X kg-1, followed three minutes later by the remainder of the 0.5 mg X kg-1 dose. Patients were anaesthetized throughout the study. When atracurium was given as a single bolus of 0.5 mg X kg-1, the mean time to complete neuromuscular block was 141.5 seconds. Administration in divided doses accelerated the onset time (p less than 0.01), that is the time from the intubating dose to the complete suppression of train-of-four (TOF) response. The TOF ratio decreased slightly but statistically significantly following the priming doses. When the priming dose was 0.05 mg X kg-1, the mean onset time was 70.9 seconds and priming with larger doses did not add any further advantage. It is concluded that 0.05 mg X kg-1 appears to be the optimal priming dose for the administration of atracurium in divided doses. When 0.05 mg X kg-1 is given three minutes before the intubating dose, tracheal intubation can be accomplished in less than 90 seconds.

Different priming techniques, including mivacurium, accelerate the onset of rocuronium

“…This observation is in agreement with the results of other studies. 5,10,13 In conclusion, this study demonstrates that priming with rocuronium 0.06 mg-kg -I or mivacurium 0.015 mg. kg -I followed three minutes later by rocuronium 0.54 mg-kg -l resulted in a neuromuscular block which was similar to that of succinylcholine 1.0 mg-kg -~ in both the onset of action and intubating conditions. This study also illustrates that the priming technique can reduce the onset time of both mivacurium (by approximately 40%) and rocuronium (by approximately 20-35%).…”

The Pharmacodynamics of Vecuronium in Chronic Renal Failure Patients: The Impact of Different Priming Doses

“…Similar observations were reported by many other authors using priming dose with different neuromuscular blockers. [17][18][19] Priming action mechanism could be explained by the wide safety margin in neuromuscular transmission. Approximately, 75% of nicotinic receptors have to be occupied for any neuromuscular function change as evaluated by acceleromyography.…”

In Vitro Investigation of the Priming Principle for Rapid Neuromuscular Block

“…However, the model accords with several clinical studies and permits generalizations. Small increases in priming doses did not substantially increase the effectiveness of priming in clinical studies [6,15]. The model indicates that the decreased onset time of small increases in priming dose or interval would be small and would be obscured by the variable responsiveness of nervemuscle systems to non-depolarizing blocking drugs in clinical settings [20].…”