Halothane Vecuronium

DM Fisher. Neuromuscular effects of vecuronium (ORG NC45) in infants and pediatric patients during N20 halothane anesthesia. Anesthesiology 58 519, 1983. 

Muscle relaxants may also contribute to anesthesia. Pancuronium 0.1 mg/kg has been reported to lower the MAC for halothane by 25% (135). It was conjectured that this could be due to a central effect or peripheral effect, through reduction of afferent input from muscle spindles to the reticular activating system. Recently, however, a similar though not identical study (SEDA-15, 124) (136) failed to confirm that pancuronium, vecuronium, or atracurium lowers the MAC for halothane. 

Rupp SM, Miller RD, Gencarelli PJ. Vecuronium-induced neuromuscular blockade during enflurane, isoflurane, and halothane anesthesia in humans. Anesthesiology 1984 60(2) 102-5. 

Fahey MR, Sessler Dl, Cannon JE, Brady K, Stoen R, Miller RD. Atracurium, vecuronium, and pancuroninm do not alter the minimum alveolar concentration of halothane in humans. Anesthesiology 1989 71(l) 53-6. 

Gregoretti SM, Sohn YJ, Sia RL. Heart rate and blood pressure changes after ORG NC45 (vecuronium) and pancuronium during halothane and enflurane anesthesia. Anesthesiology 1982 56(5) 392-5. 

One study in children found that the potentiation of vecuronium was greater with isoflurane than with enflurane, and halothane had a lesser... 

The dosage of the neuromuscular blocker may need to be adjusted according to the anaesthetic in use. For example, the dosage of atracurium can be reduced by 25 to 30% if, instead of balanced anaesthesia (with thiopental, fentanyl and nitrous oxide/oxygen)," enflurane is used, and by up to 50% if isoflurane or desflurane are used. Another study recommended reduced doses of neuromuscular blockers such as atracurium and tubocurarine in children undergoing anaesthesia with enflurane or isoflurane. In one study, enflurane and isoflurane reduced the vecuronium infusion rate requirements by as much as 70%, when compared with fentanyl anaesthesia. Another study demonstrated that although halothane and isoflurane could both increase the neuromuscular potency of vecuronium, only isoflurane prolonged the recovery from neuromuscular blockade. ... 

Cardiac arrhythmias can develop during the concurrent use of halothane and aminophylline but this seems less likely with isoflu-rane. One report attributes seizures to an interaction between ketamine and aminophylline. Supraventricular tachycardia occurred in a patient taking aminophylline when pancuronium was given. Isolated cases suggest that the effects of pancuronium, but not vecuronium, can be opposed by aminophylline. 

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