What is the recommended dose of Dantrolene (Dantrolene) for treating malignant hyperthermia?

Dantrolene Dosing for Malignant Hyperthermia

The initial dose of dantrolene for treating malignant hyperthermia should be 2-2.5 mg/kg based on actual body weight, administered immediately by rapid intravenous push, with subsequent doses of 1 mg/kg every 5-10 minutes until symptoms subside. 1, 2

Initial Dosing Protocol

• Initial dose: 2-2.5 mg/kg based on actual body weight 1

  • For adults: Maximum initial dose of 300 mg
  • For children: Same weight-based dosing as adults (2-3 mg/kg) 3
  • Base dosing on actual body weight, not ideal body weight, even in obese patients 3

• Administration technique:

  • Administer each syringe as soon as it is reconstituted rather than waiting for the complete initial dose to be prepared 3, 1
  • Give by continuous rapid intravenous push 2

Subsequent Dosing

• Follow-up doses: 1 mg/kg every 5-10 minutes 1, 2
• Continue until: Signs of malignant hyperthermia regress 1 or maximum cumulative dose of 10 mg/kg has been reached 2
• If symptoms persist: When a cumulative dose of 10 mg/kg has been administered, reevaluate the diagnosis. If MH is still the likely diagnosis, continue dantrolene administration despite the product data sheet maximum dose 3

Treatment Goals and Monitoring

• Primary treatment targets 3, 1:

  • Reduction of ETCO2 to less than 6 kPa with normal minute ventilation
  • Core temperature < 38.5°C
  • Stabilization of heart rate
  • Resolution of muscle rigidity

• When to pause: When treatment goals are achieved, pause dantrolene administration, but be prepared for potential recrudescence 3

Recrudescence Management

• Recrudescence risk: Occurs in approximately 10-15% of cases, reported up to 14 hours after control of the initial reaction 3, 1
• If recrudescence occurs within 6 hours: Administer 1 mg/kg 3, 1
• If recrudescence occurs after 6 hours: Administer 2-3 mg/kg 3, 1

Important Considerations

• Continuous infusion: Not recommended due to high incidence of thrombophlebitis 3, 1
• Prophylactic post-crisis dantrolene: Not routinely recommended as it's not required in most cases and can cause muscle weakness and nausea 3
• Post-crisis follow-up: Oral dantrolene 4-8 mg/kg/day in four divided doses for 1-3 days following a crisis to prevent recurrence 2
• Reconstitution: Each vial should be reconstituted with 60 mL of sterile water for injection (without bacteriostatic agent) and used within 6 hours 2

Side Effects to Monitor

• Muscle weakness (21.7% of cases) 4
• Phlebitis (9% of cases) 4
• Gastrointestinal upset (4.1% of cases) 4
• Respiratory failure (3.8% of cases) 4

Clinical Pearls

• Higher doses of dantrolene may be required in severe cases. One case report documented successful treatment with up to 42 mg/kg 5
• The risk of complications increases by approximately 25-29% when the total dantrolene dose is doubled 4
• Dantrolene works by reducing myoplasmic free calcium concentration, which is elevated in MH-susceptible individuals 6
• Aggressive body cooling should be implemented alongside dantrolene administration, especially in severe cases 3