Atracurium with anesthesia

Nevertheless, some interactions of benzodiazepines with muscle relaxants used in anesthesia have been described. Diazepam has been reported to potentiate the effects of tubocurare (163) and gallamine (164) and to reduce the effects of suxamethonium (164). However, in 113 patients undergoing general anesthesia, intravenous diazepam 20 mg, lorazepam 5 mg, and lormetaze-pam 2 mg did not potentiate the neuromuscular blocking effects of vecuronium or atracurium (162). 

In 113 patients undergoing general anesthesia, intravenous midazolam 15 mg slowed recovery of the twitch height after vecuronium and atracurium compared with diazepam. The recovery index was not altered (162). However, in another study in 20 patients, midazolam 0.3 mg/kg did not affect the duration of blockade, recovery time, intensity of fasciculations, or adequacy of relaxation for tracheal intubation produced by suxamethonium 1 mg/kg, nor the duration of blockade and adequacy of relaxation for tracheal intubation produced by pancuronium 0.025 mg/kg in incremental doses until 99% depression of muscle-twitch tension was obtained (161). Furthermore, in 60 patients undergoing maintenance anesthesia randomly assigned to one of six regimens (etomidate, fentanyl, midazolam, propofol, thiopental plus nitrous oxide, or isoflurane plus nitrous oxide), midazolam did not alter rocuronium dosage requirements (165). 

In man, potentiation and prolongation of the action of atracurium by halothane (62-64) have been reported, as has potentiation after 30 minutes of isoflurane anesthesia (65). Whether the dose of atracurium should be reduced from that used during balanced anesthesia by 20, 30, or 50% when patients are anesthetized with inhalational anesthetics can only be decided in the case of an individual patient if neuromuscular monitoring is available, since many other variables, such as the tissue concentrations of the volatile anesthetic and the response of the individual patient to the neuromuscular blocking drug, will influence the overall blocking effect. 

A 7-year-old boy with trisomy 21 (Down syndrome) had explosive coughing, 30 seconds after fentanyl 50 pg (2 pg/kg) had been injected and flushed through an intravenous cannula. The cough was unproductive and persisted in spasmodic bursts for a further 2-3 minutes until anesthesia was induced with propofol 60 mg and atracurium 15 mg intravenously. The coughing immediately ceased. A petechial rash in the conjuncti-vae and periorbital regions was subsequently noted and disappeared by the end of the first postoperative day. 

Tobias JD, Johnson JO, Sprague K, Johnson G. Effects of rapacuronium on respiratory function during general anesthesia a comparison with cis-atracurium. Anesthesiology 2001 95(4) 908-12. 

Pancuronium can be administered i.v. during general anesthesia at a dose rate of 0.08 mg/kg (Muir Hubbell 1989). If used appropriately, adverse effects are rare. Pancuronium and vecuronium produce minimal cardiovascular effects, although pancuronium can potentially stimulate the release of norepinephrine (noradrenaline), resulting in increased heart rate and blood pressure. Horses with pre-existing cardiovascular disease may develop hypotension. Atracurium... 

NMBAs are further differentiated by their duration of action during anesthesia. Succinylcholine and mivacurium are common ultra-short-acting competitive NMBAs (5-10 min). An intermediate duration of action (30-45 min) is maintained with the use of atracurium, cisatracurium, rocuronium and vecuronium. A long-lasting duration of action (90-100 min) is observed with d-tubocurarine, doxacurium, metocurine, pancuronium and pipecuronium. 

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