Rescue Drug Class & Adverse Effects/Clinical Pearls

Question 1

Inhaled Short-Acting B2 Agonists (SABA)

Answer 1

increase in cAMP, antagonizes bronchoconstriction -> smooth muscle relaxation (reverse obstruction and improve airflow)
AE: tachycardia, tremor, hypokalemia, irritability

albuterol
- chronic use (>2 times per day) indicates poor asthma control
- may mix nebulizer solution with cromolyn solution, budesonide inhalant suspension, or ipratropium solution
- in mild to moderate exacerbations, MDI plus valved holding chamber is as effective as nebulized therapy with appropriate administration technique and coaching by trained personnel

levalbuterol
- reserved for patients who do not respond to albuterol for quick relief
- nebulizer solution compatible with budesonide inhalant suspension
- levalbuterol administered in ½ the mg dose of albuterol provides comparable efficacy and safety
- has not been evaluated by continuous nebulization

Question 2

Short-Acting Anticholinergics

Answer 2

competitively inhibit cholinergic receptors in bronchial smooth muscle -> decrease in cGMP -> bronchodilation

ipratropium
AE: dry mouth, urinary retention, infection, sinusitis, bronchitis

used in combo with albuterol for asthma exacerbation treatment
- may mix in same nebulizer with albuterol

• should not be used as first-line therapy - should be added to SABA therapy for severe exacerbations

ipratropium/albuterol inhaler
AE: see individual products

ipratropium/albuterol nebulizer solution
- may be used for up to 3 hours in initial management of severe exacerbations

Question 3

Systemic Corticosteroids

Answer 3

decreased inflammation, increased response to B2 agonists
AE: short-term use - hyperglycemia, increased appetite, fluid retention, demargination of WBCs, psychiatric disturbances

CI: systemic fungal infections, administration of live vaccines if immunocompromised
DI: Warfarin INR­ increase & decreases efficacy of inactivated vaccines

• may be used with ICS if patient is already taking ICS before hospitalization
• may also be used for chronic therapy in both asthma (and COPD) only in severe stages
• “bursts” effective for establishing control when initiating therapy or during period of gradual deterioration
• injection may be used in place of “burst” if adherence is an issue or patient is vomiting

Question 4

Systemic (Subcutaneous B2 Agonists)

Answer 4

• no proven advantage of systemic therapy over aerosol
• indicated in addition to standard therapy for acute asthma associated with anaphylaxis and/or angioedema (epinephrine)

Question 5

Magnesium Sulfate

Answer 5

smooth muscle relaxation through inhibition of calcium influx into smooth muscle cells
AE: flushing, hypotension, vasodilation

CI: heart block & caution in renal dysfunction

• consider if patient remains in life-threatening exacerbation after 1 hour of therapy