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EMFANA

Emergency Medications for Anaesthesia Nurses Australia

** Malignant hyperthermia

What is dantrolene?

Dantrolene is used to treat malignant hyperthermia (which is caused by certain anaesthetic gases and succinylcholine muscle relaxant). In MH, the muscle go are overactive, developing symptoms of muscle rigidity, high heart rate, high CO2, high temperature, and eventual muscle breakdown. Dantrolene stops abnormal calcium release inside skeletal muscle which drives the crisis.

Common Adult Dose dantrolene

  • IV dantrolene dosage is  2.5mg per kilogram of patients weight every 5 mins or repeated until patient improves. So an 80kg adult would need a dose of 200mg

  • NOTE! vials are usually 20mg and should be mixed with 60ml of STERILE WATER for injection. This mean you will need 10 vials and 600ml of sterile water for injection and lots of 60ml syringes for just an 80kg adult

Typical Volume found in vials if dantrolene

  • often 1 vial of powder is 20mg (which will need to be reconstituted with WATER for injection

Example of preparing dantrolene

  • NOTE! vials are usually 20mg of powder and should be mixed with 60ml of STERILE WATER for injection. This mean you will need 10 vials and 600ml of sterile water for injection and lots of 60ml syringes for just an 80kg adult

Acute management of malignant hyperthermia

  • Call for help immediately.

  • Stop all anaesthetic trigger agents straight away.

  • Keep the patient asleep using other drugs such as hypnotics and opioids.

  • If muscle relaxation is needed, use a non-depolarising neuromuscular blocking drug (rocuronium, pancuronium, atracurium, cistatracurium)

  • Stop or finish the surgery as soon as safely possible.

  • Hyperventilate the patient with 100% oxygen.

  • Start cooling the patient if their temperature is high, for example with cold normal saline and other cooling methods.

  • Maintain good urine output to help protect the kidneys.

  • Give inotropes if needed to support blood pressure and circulation.

  • Treat acidosis with sodium bicarbonate (HCO3): 2–4 mEq/kg.

  • Give dantrolene 2.5 mg/kg, repeating every 5 minutes until the patient improves. Ongoing treatment may be needed because malignant hyperthermia can come back.

  • If there are cardiac arrhythmias, they may be treated with beta blockers or lignocaine.

  • If the potassium is high, treat with glucose and insulin, and consider frusemide.

  • Watch for DIC and check blood tests and creatine kinase (CK) every 6 hours.

  • (1) increased ETCO2
    (2) tachycardia
    (3) tachypnoea
    (4) masseter spasm (if develops this convert to a MH safe anaesthetic)
    (5) muscle rigidity
    (6) temp increase (late) – 1 C\15min

Disclaimer

This website is provided for general educational and informational purposes only. It is not intended to replace hospital policy, clinical judgment, official guidelines, medication charts, or advice from a qualified medical practitioner. Users are solely responsible for verifying all drug information, dosages, indications, contraindications, and administration requirements before clinical use. The owners and authors of this website accept no liability for any loss, injury, or damage arising from reliance on the information provided.

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