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Differences in rocuronium over other non-depolarizing muscle relaxants (NDMR) include which of the following?

A. More rapid onset of action

B. Metabolism by pseudocholinesterase

C. Shorter duration of action

D. Lack of potentiation with aminoglycoside antibiotics

E. Active metabolism by liver enzymes

Answer

Intubating conditions rated at 30-s intervals after rocuronium 0.6 mg/kg, vecuronium 0.1 mg/kg, or atracurium 0.5 mg/kg in children. Intubation was attempted every 30 s, beginning 30 s after drug administration, until intubation could be achieved with acceptable conditions (i.e., good or excellent). Once intubation was accomplished, no further attempts were made. A significant difference (P < 0.05) exists for rating excellent intubating conditions at the point of successful intubation in the rocuronium group compared with the vecuronium as well as the atracurium group.(Scheiber G1, Ribeiro FC, Marichal A, Bredendiek M, Renzing K. Intubating conditions and onset of action after rocuronium, vecuronium, and atracurium in young children. Anesth Analg. 1996 Aug;83(2):320-4.)

The answer is A. Of the nondepolarizing muscle relaxants in current use, rocuronium has the most rapid onset of action at clinically indicated dosages. Rocuronium is a nondepolarizing neuromuscular relaxant with an intermediate duration of action in adults, although this duration of action may be prolonged in infants and may be classified as a long-acting NMBD. Its duration of action in adults is similar to vecuronium, atracurium, and cisatracurium. Rocuronium may have a prolonged duration of action in patients with renal or hepatic dysfunction, especially at higher dosing (2-3 x ED95). At an ED95 dose (0.3 mg/kg), the onset time is 1.5 to 3 minutes, whereas with the other intermediate nondepolarizing muscle relaxants, the onset time is much longer (3 to 7 minutes). Increasing the dosage of rocuronium to 2-4 x the ED95 can decrease onset time to 60-90 seconds. This makes rocuronium a viable alternative for rapid sequence induction of patients in which you may want to avoid succinylcholine (pediatric population). .

Notes

Keywords

Meakin GH. Curr Opin Anaesthesiol. 2007 Jun;20(3):227-31.Role of muscle relaxants in pediatric anesthesia.

Reynolds LM1, Lau M, Brown R, Luks A, Fisher DM. Intramuscular rocuronium in infants and children. Dose-ranging and tracheal intubating conditions.Anesthesiology. 1996 Aug;85(2):231-9.

Wikipedia:Neuromuscular-blocking_drug

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