Malignant hyperthermia - Dantrolene





  • Used in Rx of malignant hyperthermia

PD

Muscle relaxant that inhibits excitation-contraction coupling in muscle cells

  • ?via ryanodine receptors
  • c.f. Other muscle relaxants (NMBDs) acts on NMJ

SE

  • N&V
  • Muscle weakness
  • Prolongation of NMBD

PC

  • Each bottle contains

    • Dantrolene 20 mg
    • Mannitol 3 mg (required to solubilise dantrolene)

  • Needs to be reconsituted with 60mL of sterile WATER

Difficulty in preparation

  • Very time-consuming
    • Slow to dissolve
      • Faster with warm water
    • Large volumes to prepare
      • e.g. for a 70kg man
        • Each bolus = 175 mg (9 ampoules)
        • Up to 700 mg (35 ampoules)
  • Have a dedicated team to prepare solution
    • Use as many people as possible

Clinical

Dosage in MH

MH ANZ guideline:

  • 2.5 mg/kg IV every 10 to 15 min

AAGBI guideline:

  • 2.5 mg/kg initially, then 1 mg/kg every 10 to 15 min

Indication

  • Malignant hyperthermia

    • Main indication

  • Also used in:

    • Neuroleptic malignant syndrome
    • Muscle spasticity after stroke, paraplegia, cerebral palsy, etc
    • Ecstasy intoxication
    • Serotonin syndrome