| Drug | Indication | Class | Notes |
|---|---|---|---|
| Salbutamol | Asthma, COPD | SABA | First-line; fast-acting |
| Atrovent | Asthma, COPD | SAMA (Ipratropium Bromide) | – Add-on for moderate-severe cases – Best for COPD, used with SABA in asthma |
| Combivent | Asthma, COPD | SABA + SAMA | Preferred combo in exacerbations |
| Pulmicort | Asthma (esp. peds) | ICS | Bridge if systemic steroids delayed |
| Adrenaline neb | Croup, stridor | Alpha agonist | Used for upper airway edema |
| Hypertonic Saline 3% | Bronchiolitis | Mucolytic | Mostly pediatric; use varies |
IV Magnesium Sulfate (MgSO₄) and IV Aminophylline are second- or third-line therapies in acute severe asthma, and very selectively used in COPD exacerbations.
IV Magnesium Sulfate (MgSO₄)
🧾 When to Use
- Severe/life-threatening asthma not responding to:
- Repeated nebulized bronchodilators (SABA + ipratropium)
- Systemic corticosteroids
- PEFR or FEV₁ <50% predicted
- Silent chest, exhaustion, hypoxia
- Also used in children with severe asthma (common in pediatric ED protocols)
💉 Dosage
| Age Group | Dose |
|---|---|
| Adults | 1.2–2 g IV over 20 minutes |
| Children | 25–50 mg/kg IV (max 2 g) over 20–30 minutes |
🩺 Mechanism
- Smooth muscle relaxation via calcium antagonism
- Mild anti-inflammatory properties
⚠️ Precautions
- Hypotension (rare)
- Flushing, nausea
- Caution in renal impairment
IV Aminophylline (Theophylline derivative)
🧾 When to Use
- Refractory asthma not responding to:
- SABA, ipratropium, steroids, and magnesium
- More common in children (still controversial)
- Rare in adult ED asthma in modern protocols due to narrow therapeutic index and side effects
💉 Dosage
| Age Group | Dose |
|---|---|
| Adults | Loading dose: 5–6 mg/kg IV over 20–30 min (if no recent theophylline) |
| Maintenance: 0.5–0.7 mg/kg/hr | |
| Children | Same principle, adjusted for weight and age |
| Must monitor theophylline levels |
🩺 Mechanism
- Bronchodilation via phosphodiesterase inhibition
- Mild anti-inflammatory and diaphragmatic stimulation
⚠️ Precautions
- Narrow therapeutic window (10–20 mcg/mL)
Risk of toxicity → arrhythmias, seizures, nausea - Drug interactions: macrolides, fluoroquinolones
- Requires serum level monitoring → not ideal for ED unless already on it
Flow Management
Initial Nebs + Steroids
↓
Reassess
↓
Still severe? ➜ Add IV MgSO₄
↓
No improvement? ➜ Consider IV Aminophylline
↓
Respiratory failure? ➜ Intubation / ICU
1. Asthma Diagnosis
- History + Variable respiratory symptoms (wheezing, SOB, chest tightness, cough)
- Demonstrate variable expiratory airflow limitation:
- Spirometry: FEV₁/FVC < 0.75–0.80 with ≥12% and ≥200 mL reversibility
- PEFR variability >10%
🔹 2. Treatment Principles
- Treat airway inflammation (not just bronchodilation)
- Avoid SABA-only treatment — now discouraged due to increased risk of exacerbations and mortality
🔹 3. GINA Stepwise Approach (Adults & Adolescents ≥12 years)
| Step | Preferred Controller | Reliever |
|---|---|---|
| Step 1 | Low-dose ICS–formoterol (PRN) | Low-dose ICS–formoterol (PRN) |
| Step 2 | Daily low-dose ICS or PRN ICS–formoterol | Same |
| Step 3 | Low-dose ICS–LABA (maintenance) | Low-dose ICS–formoterol (PRN) |
| Step 4 | Medium-dose ICS–LABA ± add-on | Same |
| Step 5 | Refer for phenotyping and add-on biologics or tiotropium | Same |
💡 ICS = inhaled corticosteroid; LABA = long-acting beta-agonist
🔹 4. Preferred Reliever (All Steps)
✔️ Low-dose ICS–formoterol (SMART approach):
- Prevents over-reliance on SABA
- Reduces risk of severe exacerbations
🔹 5. Acute Exacerbation Management (ED or Primary Care)
🧭 Mild–Moderate:
- SABA via MDI + spacer (or neb)
- Oral corticosteroids (e.g., prednisone 40–50 mg)
- Continue ICS or ICS–LABA
⚠️ Severe:
- Oxygen (SpO₂ ≥94%)
- SABA + ipratropium (neb q20min x3)
- Oral/IV corticosteroids
- Add IV MgSO₄ if poor response
- Consider ICU, intubation, or escalation
