What is the recommended dose of Deflazacort (Deflazacort) for patients with Duchenne muscular dystrophy?

Deflazacort Dosing for Duchenne Muscular Dystrophy

The recommended dose of deflazacort for patients with Duchenne muscular dystrophy is 0.9 mg/kg/day administered orally once daily. 1

Dosing Guidelines and Administration

• Deflazacort is FDA-approved for DMD patients 5 years of age and older 1
• The standard dosing protocol is 0.9 mg/kg/day administered once daily 2, 1
• For patients with pre-existing weight or behavioral concerns, deflazacort may be considered as first-line over prednisone 2
• Available tablet strengths: 6 mg, 18 mg, 30 mg, and 36 mg 1

Dose Adjustments and Considerations

• For ambulatory patients, the dose is commonly increased as the child grows, up to a maximum weight of 40 kg, with a deflazacort cap of 36-39 mg/day 2
• For non-ambulatory teenagers above 40 kg, the dose per kilogram may be allowed to drift down to 0.3-0.6 mg/kg/day, which still provides substantial benefit 2
• If side effects become unmanageable:
  • Reduce daily dosage by 25-33% and reassess in 1 month
  • If side effects persist, consider additional 25% reduction on daily schedule 2

Alternative Dosing Regimens

If side effects are unmanageable on daily dosing, alternative regimens may be considered:

• Alternate day: 2 mg/kg every other day (less effective but may have fewer side effects) 2
• Intermittent: 0.6 mg/kg on days 1-20 and none for the remainder of the month (less effective but may have fewer side effects) 2

Important Clinical Considerations

• Continue deflazacort even when patients become non-ambulatory to slow scoliosis progression, decline in pulmonary function, and possibly heart failure 2
• 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 2
• Ensure immunization schedule is complete before initiating deflazacort 2
• Monitor for common side effects including Cushingoid appearance, weight gain, increased appetite, upper respiratory tract infection, and hirsutism 1

Recent Research Insights

A 2022 randomized trial comparing 0.45 mg/kg/day vs. 0.9 mg/kg/day found that the lower dose did not meet non-inferiority criteria in the general DMD population, supporting the standard 0.9 mg/kg/day dosing 3. However, the lower dose showed potential non-inferiority in younger patients (≤7 years) with better baseline function (6MWD >350m) 3.

Common Pitfalls to Avoid

• Discontinuing deflazacort prematurely due to side effects without first attempting dose adjustments
• Failing to monitor for side effects, particularly weight gain, Cushingoid features, and bone demineralization
• Not providing vitamin D and calcium supplementation to reduce osteoporosis risk
• Administering live or live-attenuated vaccines to patients on deflazacort (should be given at least 4-6 weeks prior to starting therapy) 1

Drug Interactions

• When using moderate or strong CYP3A4 inhibitors, reduce deflazacort dose to one-third of the recommended dosage 1
• Avoid use with moderate or strong CYP3A4 inducers as they may reduce efficacy 1

Remember that attentive management of steroid-related side effects is crucial, and deflazacort should be managed in clinics with appropriate expertise in DMD care 2.