What drugs are of proven therapeutic value in acute severe asthma?

Drugs of Proven Therapeutic Value in Acute Severe Asthma

Oxygen, nebulized salbutamol, and parenteral glucocorticosteroids are the drugs of proven therapeutic value in acute severe asthma, with intravenous amoxicillin and disodium cromoglycate having no established role in immediate management. 1, 2

First-Line Medications

1. Oxygen

• Essential in all cases of acute severe asthma
• Recommended at 40-60% concentration 1
• Helps correct hypoxemia which is common in severe asthma attacks
• Should be administered immediately upon presentation

2. Nebulized Salbutamol (β-agonist)

• First-line bronchodilator for rapid reversal of airflow obstruction 2
• Dosage: 5 mg for adults via nebulizer 1, 2
• Administration frequency: Initially every 20 minutes for 3 doses, then as needed 2
• Can be delivered via oxygen-driven nebulizer for maximum benefit 1
• Mechanism: Relaxes bronchial smooth muscle by increasing cyclic AMP 3

3. Parenteral Glucocorticosteroids

• Essential for all patients with acute severe asthma 1
• Options include:
  • Prednisolone 30-60 mg orally 1
  • Intravenous hydrocortisone 200 mg 1
• Should be administered as early as possible as clinical benefits may take 6-12 hours to manifest 4
• Reduces airway inflammation and enhances responsiveness to β-agonists

Second-Line/Adjunctive Medications

Ipratropium Bromide

• Add to nebulized β-agonist if patient not improving after 15-30 minutes 1
• Dosage: 0.5 mg nebulized, repeat 6-hourly until improvement starts 1
• Provides additional bronchodilation through anticholinergic mechanism
• Particularly beneficial in severe cases not responding to β-agonists alone 5

Assessment of Severity

Objective Measures:

• Peak Expiratory Flow (PEF): <50% of predicted indicates severe asthma 1
• Respiratory Rate: >25 breaths/min indicates severe asthma 1
• Heart Rate: >110 beats/min indicates severe asthma 1
• Speech Pattern: Inability to complete sentences in one breath 1

Treatment Algorithm

1. Initial Assessment:

   • Measure PEF, respiratory rate, heart rate, oxygen saturation
   • Assess ability to speak in complete sentences

2. Immediate Treatment:

   • Administer oxygen 40-60%
   • Give nebulized salbutamol 5 mg
   • Administer systemic corticosteroids (oral prednisolone or IV hydrocortisone)

3. Reassessment after 15-30 minutes:

   • If improving: Continue oxygen and scheduled salbutamol
   • If not improving: Add ipratropium bromide 0.5 mg to nebulizer
   • Increase frequency of nebulized salbutamol (up to every 30 minutes)

4. Monitoring:

   • Continuous monitoring of respiratory rate, heart rate, oxygen saturation
   • Repeat PEF measurements to assess response

Common Pitfalls and Caveats

1. Underestimating Severity:

   • Delay in recognizing severe asthma can be fatal 1
   • Always assess objectively with PEF measurements

2. Underuse of Corticosteroids:

   • Delaying corticosteroid administration worsens outcomes 1
   • Administer early even if response not immediately apparent

3. Overreliance on β-agonists:

   • Excessive use without addressing underlying inflammation is ineffective 2
   • Always combine with corticosteroids

4. Medication Side Effects:

   • Monitor for tachycardia with salbutamol, especially with IV administration 6
   • Be cautious with aminophylline in patients already taking theophyllines 1

5. Intravenous Amoxicillin:

   • Not indicated for routine management of acute asthma unless clear evidence of bacterial infection
   • No proven benefit in acute asthma management

6. Disodium Cromoglycate:

   • Preventive medication with no role in acute severe asthma
   • Too slow-acting to be beneficial in emergency situations

Remember that early, aggressive treatment with the proven therapies (oxygen, nebulized salbutamol, and systemic corticosteroids) is essential to prevent morbidity and mortality in acute severe asthma.