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Neuromuscular Blocker

Succinylcholine

Depolarizing NMBA · Anectine, Quelicin

Mechanism: ACh receptor agonist → sustained depolarization → flaccid paralysis.

Calculate dose for your patient

Enter weight (kg or lb). Always verify before administration.

Computed weight
70.0 kg · 154.3 lb
Intubation
70 mg – 105 mg
= 3.50–5.25 mL (20 mg/mL)
Peds infants 2 mg/kg. IM 3–4 mg/kg.

Weight is saved on this device for the next calculator you open.

Full dose calculator
Onset
30–60 sec
Duration
5–10 min
Metabolism
Plasma pseudocholinesterase (butyrylcholinesterase).

Dosing

Adult
1–1.5 mg/kg IV (defasciculate first with non-depolarizer if desired). IM: 3–4 mg/kg.
Pediatric
IV: 2 mg/kg (infants); 1–1.5 mg/kg (children). IM: 4 mg/kg.

Indications

  • Rapid sequence intubation
  • Laryngospasm
  • Brief paralysis

Contraindications

  • History or family hx of malignant hyperthermia
  • Hyperkalemia (K+ rises ~0.5 mEq/L; up to 5–10 mEq/L in susceptible)
  • Major burns >24–48 h old
  • Denervation injury / prolonged immobility
  • Muscular dystrophy (Duchenne)
  • Pseudocholinesterase deficiency

Side Effects

  • Fasciculations & myalgia
  • Hyperkalemia
  • Bradycardia (esp. peds, repeat dosing)
  • Increased intragastric / IOP / ICP
  • MH trigger

Clinical Pearls

1Pretreat peds with atropine 0.02 mg/kg to prevent bradycardia.
2Prolonged block (>1 h) → suspect pseudocholinesterase deficiency.

References & Further Reading

  1. 1
    Textbook

    Flood P, Rathmell JP, Shafer S. Stoelting's Pharmacology and Physiology in Anesthetic Practice. 5th ed. Philadelphia: Wolters Kluwer; 2015.

  2. 2
    Textbook

    Gropper MA, Miller RD, Cohen NH, et al., eds. Miller's Anesthesia. 9th ed. Philadelphia: Elsevier; 2020.

  3. 3
    Textbook

    Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC, Ortega R, Sharar SR, Holt NF. Clinical Anesthesia. 8th ed. Philadelphia: Wolters Kluwer; 2017.

  4. 4
    SocietyOpen source

    Malignant Hyperthermia Association of the United States (MHAUS). Recognition and Treatment of MH. Hotline 1-800-MH-HYPER. mhaus.org.

  5. 5
    Textbook

    Adriano A, Morris R, eds. 2021 CA-1 Tutorial Textbook (15th Ed.). Stanford University Medical Center, Department of Anesthesiology.

Citations are provided to direct further study. Always check the most current edition of guidelines and society recommendations — the information in this chapter is a teaching summary, not primary source material.