In an adult with an acute asthma exacerbation, should I use oral prednisone or intravenous methylprednisolone, and what are the appropriate dosing regimens for moderate versus severe attacks?

Oral Prednisone vs Intravenous Methylprednisolone for Acute Asthma Exacerbations

Oral prednisone is equally effective as intravenous methylprednisolone for acute asthma exacerbations and should be used as first-line therapy in all patients who can tolerate oral intake. 1

Route Selection Algorithm

Step 1: Assess oral tolerance

• If the patient can swallow and is not actively vomiting, prescribe oral prednisone 40–60 mg once daily (or divided twice daily) for adults 1, 2
• Oral administration provides anti-inflammatory efficacy equivalent to IV therapy when gastrointestinal absorption is intact 1, 3, 4

Step 2: Reserve IV therapy for specific contraindications

• Use IV methylprednisolone 40–80 mg/day (or hydrocortisone 200 mg immediately, then 200 mg every 6 hours) only if the patient is actively vomiting, severely ill and unable to swallow, or has impaired GI absorption 1, 2, 5
• A randomized controlled trial in 66 hospitalized children found no difference in length of stay between oral prednisone and IV methylprednisolone (70 vs 78 hours, p=0.52), but oral therapy required less supplemental oxygen (30 vs 52 hours, p=0.04) 3
• A randomized trial in 65 adults with acute exacerbations showed equivalent improvement in peak expiratory flow at 72 hours between oral prednisolone 100 mg daily and IV hydrocortisone 100 mg every 6 hours (53.2% vs 55.9% predicted, p=0.28) 4

Dosing by Severity

Moderate exacerbations (PEF 40–69% predicted, can speak in sentences, respiratory rate <25/min, pulse <110/min):

• Prednisone 40 mg once daily until PEF reaches ≥70% of predicted or personal best 1, 2
• Continue for 5–10 days without tapering 1

Severe exacerbations (PEF <50% predicted, difficulty completing sentences, respiratory rate ≥25/min, pulse ≥110/min, or oxygen desaturation):

• Prednisone 60 mg once daily (or 40–80 mg in divided doses) until PEF reaches ≥70% of predicted 1, 2
• If IV route is necessary, methylprednisolone 40–80 mg/day or hydrocortisone 200 mg every 6 hours 1, 5

Life-threatening features (PEF <33% predicted, silent chest, cyanosis, confusion, exhaustion):

• Prednisone 60–80 mg daily if oral route feasible, otherwise IV hydrocortisone 200 mg immediately then 200 mg every 6 hours 2

Critical Evidence on Dose Equivalence

• A Cochrane systematic review of 344 adults found no clinically or statistically significant differences in FEV₁ improvement at 24,48, or 72 hours when comparing low-dose (≤80 mg methylprednisolone/day), medium-dose (80–360 mg/day), and high-dose (>360 mg/day) corticosteroids 6
• A randomized trial comparing methylprednisolone 1 mg/kg/day vs 6 mg/kg/day found identical improvement in FEV₁ at 44 hours (53% vs 45% predicted, NS), demonstrating that high doses offer no additional benefit 7

Duration and Tapering

• Total course lasts 5–10 days for outpatient management 1
• Continue until PEF reaches ≥70% of predicted or personal best 1, 2
• No tapering is required for courses <7–10 days, especially when patients are concurrently using inhaled corticosteroids 1
• Tapering short courses is unnecessary and may lead to underdosing during the critical recovery period 1

Timing of Administration

• Administer systemic corticosteroids within 1 hour of emergency department presentation for all moderate-to-severe exacerbations 1
• Early administration is essential because anti-inflammatory effects require 6–12 hours to become clinically apparent 1, 2, 5
• Delaying corticosteroid therapy while repeatedly giving bronchodilators alone is a dangerous and common pitfall 1, 2

Concurrent Essential Therapy

• Nebulized albuterol 2.5–5 mg every 20 minutes for three doses, then every 1–4 hours as needed 1
• Supplemental oxygen to maintain SpO₂ >92% (>95% in pregnant women and patients with heart disease) 2
• Add ipratropium bromide 0.5 mg to nebulized β-agonist for severe exacerbations 1, 2

Monitoring Response

• Measure peak expiratory flow 15–30 minutes after starting treatment and continue monitoring according to response 1, 2
• If no improvement within 15–30 minutes of initial bronchodilator and corticosteroid treatment, increase nebulized β-agonist frequency to every 30 minutes and consider hospital admission or ICU transfer 1, 2

Common Pitfalls to Avoid

• Never use unnecessarily high doses (>60–80 mg prednisone-equivalent); higher doses provide no additional clinical benefit but increase adverse effects 1, 6, 7
• Never delay systemic corticosteroids while delivering repeated bronchodilator doses alone; underuse of corticosteroids is a documented cause of preventable asthma deaths 1, 2
• Never choose IV over oral therapy when the patient can tolerate oral intake; oral administration is equally effective, less invasive, and approximately 10 times less expensive than IV therapy 1, 3
• Never taper short courses (<7–10 days); this is unnecessary and may result in underdosing during the critical period 1

Pediatric Dosing

• Prednisone or prednisolone 1–2 mg/kg/day in two divided doses (maximum 60 mg/day) for 3–10 days without tapering 1
• Calculate dose using ideal body weight in overweight children to avoid excessive steroid exposure and behavioral side effects 1
• A randomized trial in hospitalized children found oral prednisone 2 mg/kg twice daily was equivalent to IV methylprednisolone 1 mg/kg four times daily, with no difference in length of stay 3