First-lineAnectine / Scoline

Suxamethonium

Depolarising neuromuscular blocker

Rapid sequence induction paralysing agent in obstetric GA.

IV

First-line for

  • Rapid sequence induction for obstetric GA (Category 1 LSCS, failed intubation)
  • Laryngospasm reversal

Mechanism

Non-competitive nicotinic ACh receptor agonist → sustained depolarisation → paralysis; metabolised by plasma cholinesterase (~5 min).

"Sux = SUX side effects but SUB-second onset"

  • Hyperkalaemia in burns/spinal injury >48h old
  • Malignant hyperthermia trigger
  • Prolonged block if plasma cholinesterase deficiency

Dosing

RSI
1–1.5 mg/kg IV

Contraindications

  • AbsolutePersonal or family history of malignant hyperthermia
  • AbsoluteBurns >24 h old, denervation, prolonged immobilisation (hyperK)
  • AbsolutePlasma cholinesterase deficiency (relative — use rocuronium)

Side effects

  • Fasciculations, myalgia
  • Hyperkalaemia
  • Bradycardia (repeat dose)
  • Malignant hyperthermia
  • Anaphylaxis (top NMB culprit)

Fetal & maternal notes

  • Highly ionised — minimal placental transfer at RSI doses

Key interactions

  • Aminoglycosides / Mg

    Caution

    Prolonged block

Clinical pearls

  • 💡 Rocuronium + sugammadex is a modern alternative for RSI
  • 💡 Have adrenaline and dantrolene protocol ready

Content last reviewed: REPLACE_ME (e.g. 2026-07)

Spotted something out of date? See our disclaimer or use Report an Error above.

For educational use only

Not medical advice. Verify dosing against the BNF and your local trust guidelines before prescribing.