Dose—response Curves for Suxamethonium in Neonates, Infants and Children

Abstract

Single dose-response curves were determined for suxamethonium in neonates, infants and children during thiopentone-fentanyl-nitrous oxide anaesthesia. During onset of neuromuscular block, suxamethonium produced an increase in muscle tone which was greatest in neonates and infants. The dose-response curves for the three groups were parallel. The effective doses producing 90% depression of twitch height were significantly greater in neonates and infants compared with children (517 and 608 v. 352 micrograms kg-1). These values were greater than those obtained in a comparable study in adults. In view of their higher ED values compared with adults and a marked individual variability in response to small doses of suxamethonium, we recommend an intubating dose of 3 mg kg-1 for neonates and infants and 2 mg kg-1 for children. These doses are 50-100% greater than those previously recommended for paediatric patients.

Should we reconsider awake neonatal intubation? A review of the evidence and treatment strategies

“…Suxamethonium has been widely studied and used safely in infants including some studies based in neonatal units (10,23). The dose required for neonatal intubation, 2–3 mg·kg –1 , is higher than that required in adults which is partly due to a proportionally larger volume of distribution but may also be related to immaturity of the neuromuscular junction (86,87). Meakin et al .…”

“…Meakin et al . identified higher dose requirements in neonates and infants when compared to older children and suggested that associated muscle rigidity could be a result of underdosage (87).…”

The principles of paediatric anaesthesia

“…Suxamethonium can cause bradycardia, due to its action on the sinoatrial node, this response is exaggerated in children. 11,12 Inhalational induction e this is the preferred method in neonates and the alternative method in the event of unsuccessful intravenous cannulation. Good explanation to parent and child is again essential.…”

Succinylcholin-Update

“…Neugeborene und Säuglinge benötigen in mg/kg grö-ßere Dosen Succinylcholin [57] als Erwachsene (Abb. 2, Tabelle 4); äquipoten-te Dosen Succinylcholin wirken aber in allen Altersklassen ähnlich lang, obgleich die Aktivität der PChE im ersten Lebenshalbjahr noch kleiner ist.…”