What is the recommended dose of deflazacort?

Recommended Dose of Deflazacort

The recommended dose of deflazacort is 0.9 mg/kg/day administered orally once daily, rounded up to the nearest possible tablet strength. 1

Standard Dosing for Duchenne Muscular Dystrophy

• The FDA-approved dose is approximately 0.9 mg/kg/day once daily for patients 5 years of age and older with DMD. 1
• The American Academy of Neurology confirms this same dosing of 0.9 mg/kg/day for patients aged 6 years and older who are at a plateau or declining phase of disease. 2
• This dose should be incrementally increased with growth up to a maximum absolute dose of 36 mg/day (corresponding to a body weight of 40 kg). 3

Dose Equivalence to Prednisone

• Deflazacort 0.9 mg/kg/day is approximately equivalent to prednisone 0.75 mg/kg/day, maintaining a 6:5 conversion ratio (6 mg deflazacort = 5 mg prednisone). 4
• This conversion ratio is consistently validated across multiple clinical contexts. 4

Administration Details

• Deflazacort can be taken with or without food. 1
• Do not administer with grapefruit juice. 1
• Tablets can be swallowed whole or crushed and mixed immediately with applesauce. 1
• Any combination of the four tablet strengths (6 mg, 18 mg, 30 mg, 36 mg) can be used to achieve the target dose. 1

Dose Modifications for Drug Interactions

• When co-administered with moderate or strong CYP3A4 inhibitors, reduce the dose to one-third of the recommended dosage (e.g., 36 mg/day reduced to 12 mg/day). 1
• Avoid concurrent use with moderate or strong CYP3A4 inducers. 1

Evidence Supporting Standard Dose vs. Lower Dose

A 2022 randomized non-inferiority trial directly compared deflazacort 0.45 mg/kg/day versus 0.9 mg/kg/day in newly diagnosed DMD patients. 5 The lower dose failed to meet non-inferiority criteria, with a mean difference in 6-minute walk distance change of 24.8 meters favoring the standard 0.9 mg/kg/day dose (p=0.008). 5 This confirms that 0.9 mg/kg/day should not be reduced in most patients. 5

However, the lower dose showed non-inferiority in specific subgroups: boys ≤7 years of age and those with baseline 6MWD >350 meters. 5 Despite this, the standard 0.9 mg/kg/day remains the recommended dose given FDA approval and guideline consensus. 1, 2

Alternative Dosing Regimens (If Standard Daily Dosing Not Tolerated)

If side effects are unmanageable with daily 0.9 mg/kg/day dosing:

• First, reduce daily dosage by 25-33% and reassess in 1 month. 3
• If still intolerable, consider further 25% reduction; minimum effective daily dose of deflazacort is approximately 0.36 mg/kg/day (equivalent to prednisone 0.3 mg/kg/day). 3
• An intermittent protocol of 0.6 mg/kg/day for the first 20 days of each month has been studied, showing 97% ambulatory at 9 years and 25% at 15 years, though less effective than daily 0.9 mg/kg/day. 6

Dosing for Non-DMD Indications

• Allergic Bronchopulmonary Aspergillosis: 0.75 mg/kg/day for 4 weeks, then decreased by half every 4 weeks for 2 months, followed by tapering by 6 mg every 2 weeks until discontinuation. 2
• Acute adrenal insufficiency in pediatrics: 2-3 mg/kg (maximum 100 mg) administered in 3-5 minutes, followed by 1-5 mg/kg every 6 hours for neonates or 12.5 mg/m² every 6 hours for larger children. 2

Critical Precautions

• Complete all immunizations, particularly live vaccines, at least 4-6 weeks before starting deflazacort. 1, 2
• Never abruptly discontinue deflazacort after more than a few days of use; taper gradually to avoid potentially fatal acute adrenal insufficiency. 1, 3
• Continue treatment even when patients become non-ambulatory to retard scoliosis progression, decline in pulmonary function, and possibly heart failure. 3