Is deflazacort (corticosteroid) 6 mg twice daily (bd) sufficient for treatment?

Deflazacort Dosing in Duchenne Muscular Dystrophy

Deflazacort 6 mg twice daily (12 mg/day total) is likely insufficient for optimal treatment of Duchenne muscular dystrophy, as the recommended dose is 0.9 mg/kg/day with a maximum of 36-39 mg/day. 1, 2

Appropriate Dosing Guidelines

• The standard recommended dose for deflazacort in DMD is 0.9 mg/kg/day 1, 2
• For a patient weighing:
  • Under 13.3 kg: 6 mg twice daily (12 mg total) might be sufficient
  • Over 13.3 kg: 6 mg twice daily would be inadequate

Weight-Based Dosing Algorithm:

1. Calculate patient's weight in kg
2. Multiply by 0.9 mg/kg to determine daily dose
3. Increase dose as child grows until reaching maximum weight of 40 kg
4. Cap dose at 36-39 mg/day when patient reaches 40 kg 1, 2

Monitoring Efficacy and Side Effects

• If the patient is showing functional decline on the current dose, increase to the target dose based on weight 1
• Monitor for common side effects:
  • Cushingoid appearance
  • Weight gain (less with deflazacort compared to prednisone)
  • Behavioral changes
  • Cataracts (requires annual ophthalmological examination)
  • Bone demineralization (requires DEXA scan) 1

Dose Adjustment for Side Effects

If side effects become unmanageable:

1. Reduce daily dosage by 25-33% and reassess in 1 month
2. If still problematic, consider further 25% reduction
3. Minimum effective daily dose of prednisone equivalent is approximately 0.3 mg/kg/day 1

Alternative Regimens (If Daily Dosing Causes Intolerable Side Effects)

• Alternate day: 2 mg/kg every other day (less effective)
• Intermittent: 0.6 mg/kg on days 1-20 and none for remainder of month 1, 2

Important Considerations

• Deflazacort should be continued even when patients become non-ambulatory to slow scoliosis progression, decline in pulmonary function, and possibly heart failure 1, 2
• Deflazacort may be preferred over prednisone for patients with pre-existing weight or behavioral concerns 1, 2
• Ensure immunization schedule is complete before initiating therapy 1, 2

Pitfalls to Avoid

• Underdosing: Using a fixed dose (like 6 mg twice daily) without accounting for patient weight can lead to suboptimal treatment outcomes
• Discontinuing too early: Continuing therapy even after loss of ambulation provides important benefits for respiratory and cardiac function 1
• Abrupt discontinuation: Always taper glucocorticoids to avoid adrenal crisis
• Ignoring growth: Failure to adjust dose as the child grows can result in relative underdosing over time 1, 2

The evidence strongly supports weight-based dosing of deflazacort at 0.9 mg/kg/day for optimal management of DMD, with dose adjustments based on patient response and side effect profile.