What is the recommended dose of deflazacort (corticosteroid) for Duchenne muscular dystrophy?

Deflazacort Dosing for Duchenne Muscular Dystrophy

The recommended dose of deflazacort for Duchenne muscular dystrophy (DMD) is 0.9 mg/kg/day administered orally once daily. 1, 2

Standard Dosing Protocol

• Initial dosing: 0.9 mg/kg/day for patients 5 years of age and older 1, 2
• Maximum dose: Increase dose as child grows until reaching approximately 40 kg in weight, with a deflazacort cap of 36-39 mg/day 3, 1
• Non-ambulatory patients: Continue therapy even when non-ambulatory to slow scoliosis progression, decline in pulmonary function, and possibly heart failure 3, 1
• Dosing in older non-ambulatory teenagers: For patients above 40 kg, dose per kilogram often drifts down to 0.3-0.6 mg/kg/day range, which still provides substantial benefit 3, 1

Patient-Specific Considerations

• Deflazacort may be preferred as first-line therapy over prednisone for patients with pre-existing weight or behavioral concerns 3, 1
• Ensure immunization schedule is complete before initiating deflazacort 3, 1

Side Effect Management

If side effects become unmanageable or intolerable:

1. Reduce daily dosage by 25-33% and reassess in 1 month 3, 1
2. If side effects remain problematic, consider:
   • Further reduction (minimum effective daily dose approximately 0.3 mg/kg/day) 3
   • Alternative regimens:
     • Alternate day: 2 mg/kg every other day (less effective) 3, 1
     • Intermittent: 0.6 mg/kg on days 1-20 and none for remainder of month 3, 1

Monitoring and Adjustments

• For patients showing functional decline on a low dose, consider a "functional-rescue adjustment" by increasing to the target dose and reassessing in 2-3 months 3, 1
• Monitor for common side effects:
  • Cushingoid appearance
  • Weight gain
  • Increased appetite
  • Behavioral changes
  • Cataracts (consider ophthalmological examination)
  • Bone demineralization (consider vitamin D supplementation)

Important Clinical Considerations

• Discontinue gradually when administered for more than a few days 2
• Do not administer live or live attenuated vaccines to patients receiving immunosuppressive doses of corticosteroids 2
• Administer live-attenuated or live vaccines at least 4-6 weeks prior to starting deflazacort 2

Efficacy Considerations

Recent research indicates that lower doses (0.45 mg/kg/day) did not meet non-inferiority criteria compared to the standard 0.9 mg/kg/day dose, supporting the current recommended dosing 4. However, the lower dose may be considered in specific subgroups (age ≤7 years with baseline 6MWD >350m) if side effects are problematic 4.

Deflazacort therapy has been shown to significantly improve functional outcomes, delay loss of ambulation, reduce scoliosis development, and potentially improve long-term survival when used at the recommended doses 5, 6.