What are the recommended steroid treatment guidelines, including initiation age, dosing regimens, monitoring, and side‑effect management, for boys with Duchenne muscular dystrophy?

Steroid Treatment Guidelines for Duchenne Muscular Dystrophy

Initiation Timing

Glucocorticoid therapy should be initiated during the plateau phase of motor function, typically between ages 4–8 years, when motor skills stop progressing but before clear decline begins. 1

Three Phases of Motor Function to Guide Timing:

• Making Progress Phase (typically until age 4–6 years): Do NOT start steroids, especially if the child is under 2 years of age and still gaining motor skills 1, 2

• Plateau Phase (typically age 4–8 years): This is the optimal time to initiate therapy—when there is no longer progress in motor skills but prior to decline 1

• Decline Phase: Starting steroids is still recommended but may be of more limited benefit; characterized by longer times on timed testing, loss of skills (climbing stairs), less endurance, or more falls 1

Prerequisites Before Starting:

• Complete all recommended immunizations according to national schedule 1
• Establish varicella immunity (confirm with protective serum titer) 1
• Administer live-attenuated or live vaccines at least 4–6 weeks prior to starting deflazacort 3

Dosing Regimens

Daily prednisone at 0.75 mg/kg/day or daily deflazacort at 0.9 mg/kg/day are the recommended first-line regimens, with both showing superior efficacy compared to intermittent dosing. 4, 5

Specific Dosing:

• Prednisone: 0.75 mg/kg/day given daily 1, 4, 5
• Deflazacort: 0.9 mg/kg/day given daily 1, 4, 3, 5
• Intermittent prednisone (10 days on/10 days off): NOT recommended as initial therapy based on the FOR-DMD trial showing inferior outcomes 5

Choosing Between Prednisone and Deflazacort:

• Use prednisone as first-line unless pre-existing weight or behavioral issues favor deflazacort 6
• Switch from prednisone to deflazacort if obesity becomes concerning, as deflazacort causes less weight gain 1, 6
• Both have similar efficacy for motor function, pulmonary function, and prolonging ambulation 5, 7
• Deflazacort has a slightly different side-effect profile: less weight gain but 30% risk of asymptomatic cataracts 1, 8

Dose Adjustments:

• For significantly overweight children, dose based on ideal body weight to avoid excessive steroid exposure 2
• Increase dose for growth up to a maximum weight of 40 kg (prednisone 30 mg/day or deflazacort 36 mg/day) 4
• When used with moderate or strong CYP3A4 inhibitors, reduce deflazacort to one-third of the recommended dosage 3
• Avoid deflazacort with moderate or strong CYP3A4 inducers 3

Continuation After Loss of Ambulation

Continue glucocorticoid therapy after loss of ambulation to preserve upper limb strength, reduce scoliosis progression, and delay decline in respiratory and cardiac function. 1

• Daily dosing is indicated if there is stable or declining functional course 1
• Greater need to consider pre-existing risk factors (behavioral issues, fracture risk, obesity) in non-ambulatory patients 1
• Abnormal echocardiogram or heart failure symptoms are NOT contraindications, though advanced cardiomyopathy may carry higher risk of side-effects 1

Monitoring Requirements

Constitutional and Cosmetic:

• Cushingoid features and obesity: Implement proactive dietary management for entire family; particular vigilance if patient, parents, or siblings are obese 1
• Growth: Monitor height at least every 6 months; consider endocrine evaluation if growth plateaus 1
• Delayed puberty: Monitor Tanner stage; consider endocrine assessment if notably delayed 1
• Hirsutism, acne, tinea, warts: Forewarn parents; use ancillary treatments as needed 1

Metabolic and Cardiovascular:

• Blood pressure: Monitor at each clinic visit using age and height-specific percentiles; if >99%, reduce salt intake and consider weight reduction; if ineffective, refer for ACE inhibitor or β-blocker 1, 2
• Glucose intolerance: Urine dipstick for glucose at clinic visits; if positive, check fasting or post-prandial blood glucose and seek endocrine consultation if abnormal 1
• GERD: Enquire about symptoms; avoid NSAIDs; prescribe proton pump inhibitors if needed 1

Behavioral and Psychiatric:

• Adverse behavioral changes: Identify baseline mood, temperament, ADHD issues; consider treating baseline issues before starting steroids; consider changing timing of medication to later in day or behavioral health referral 1
• Emotional adjustment screening: Perform at every clinic visit using standardized rating scales 6

Infectious Disease and Immunosuppression:

• Adrenal suppression: Advise parents of risk of serious infection and need to promptly address minor infection; engage in tuberculosis surveillance 1
• Emergency preparedness: Provide steroid alert card listing emergency considerations for acute illness, fracture, serious infection, surgery, or general anesthesia 1, 6

Ophthalmologic:

• Cataracts: Annual screening for cataracts, especially with deflazacort (30% develop asymptomatic cataracts) 2, 6, 8

Bone Health:

• Fractures and osteoporosis: Annual DEXA scans and vitamin D monitoring for long-term use; daily vitamin D and calcium supplementation 2, 8

Side-Effect Management

Proactive Strategies:

• If side effects are unmanageable: Reduce dose by 25–33% and reassess in 1 month 6
• Do not abandon glucocorticoid therapy until at least one dose reduction and change to alternative regimen has been attempted 6
• Never stop glucocorticoids abruptly—ensure gradual taper for prolonged courses to avoid adrenal insufficiency 2, 4, 3

Common Pitfalls to Avoid:

• Starting too early: Do not initiate in children under 2 years still making motor progress—exposes to unnecessary side effects without clear benefit 2, 6
• Abandoning prematurely: Discontinuing due to side effects without attempting dose reduction or alternative regimens deprives patients of proven mortality and morbidity benefits 6
• Failing to provide emergency card: Puts patients at risk during acute illness or surgical procedures 6
• Using supplements without evidence: Do not use coenzyme Q10, carnitine, amino acids, fish oil, vitamin E, or green tea extract—insufficient evidence exists 6

Expected Outcomes

Glucocorticoid therapy significantly slows decline in muscle strength and function, prolongs ambulation by years, reduces risk of scoliosis requiring surgery, and stabilizes pulmonary and cardiac function. 1, 6, 5, 9, 7

• Boys on daily prednisone or deflazacort remain ambulatory significantly longer: 83% at 12 years vs 0% in controls, and 77% at 15 years vs 0% in controls 8
• Scoliosis >20 degrees develops in only 16–30% of treated boys vs 90% of controls 8
• Pulmonary function is preserved and respiratory insufficiency develops later 9, 7
• Cardiac symptoms are reduced 9