Common Respiratory Medications
A practical clinical reference covering the most commonly used respiratory medications — mechanisms of action, indications, dosing routes, and key clinical considerations for bedside respiratory therapists.
Written for respiratory therapists, students, and clinicians.
Short-Acting Beta-2 Agonists (SABAs)
SABAs are the foundation of acute bronchospasm treatment. They act on beta-2 adrenergic receptors in bronchial smooth muscle, triggering bronchodilation within minutes. They are the first-line "rescue" medication for acute asthma and COPD exacerbations.
Albuterol (Salbutamol)
Nebulization: 2.5 mg in 3 mL NS q4–6h or prn; MDI: 90 mcg/puff, 2 puffs prn
Most common inhaled bronchodilator; onset ~5 min, duration 4–6h; side effects: tachycardia, tremor, hypokalemia with frequent dosing
Levalbuterol (Xopenex)
Nebulization: 0.63–1.25 mg q6–8h; MDI: 45 mcg/puff
R-isomer of albuterol; fewer cardiovascular side effects in theory; more expensive; similar efficacy in most patients
Ipratropium (Atrovent)
Nebulization: 0.5 mg q4–6h; MDI: 17 mcg/puff, 2 puffs q4–6h
Anticholinergic (not technically a SABA); often combined with albuterol (Combivent, DuoNeb); useful in COPD, mild additive effect in asthma
Long-Acting Bronchodilators (LABAs and LAMAs)
Long-acting bronchodilators are the cornerstone of maintenance therapy for COPD and persistent asthma. They are not for acute rescue use and should never replace SABAs in emergencies.
Formoterol (Foradil, Perforomist)
DPI: 12 mcg capsule q12h; nebulization: 20 mcg/2 mL q12h
LABA; onset faster than salmeterol; can be used in COPD and asthma (always with ICS in asthma)
Salmeterol (Serevent)
DPI: 50 mcg/blister q12h
LABA; slower onset (~20 min); not for acute relief; black box warning: increased asthma-related death risk if used without ICS
Tiotropium (Spiriva)
DPI: 18 mcg capsule once daily
LAMA; reduces exacerbations and hospitalizations in COPD; limited role in asthma; side effects: dry mouth, urinary retention
Umeclidinium (Incruse Ellipta)
DPI: 62.5 mcg once daily
Once-daily LAMA for COPD maintenance; often combined with vilanterol (Anoro Ellipta)
Inhaled Corticosteroids (ICS)
ICS reduce airway inflammation and are the primary controller medications for persistent asthma. They reduce exacerbation frequency and improve lung function. ICS are not used for acute bronchospasm — their anti-inflammatory effects take days to weeks.
Budesonide (Pulmicort)
Nebulization: 0.25–1 mg BID; DPI: 180–360 mcg BID
Used in asthma and COPD (in combination with formoterol); most commonly nebulized ICS; well-studied in pediatric asthma
Fluticasone (Flovent)
MDI: 44–220 mcg/puff BID; DPI: 50–500 mcg BID
Widely used in asthma; combined with salmeterol (Advair) or vilanterol (Breo) for combination therapy
Beclomethasone (QVAR)
MDI: 40–80 mcg/puff BID
Extra-fine particle formulation; good deposition in small airways; does not require spacer as critically
Systemic Corticosteroids
Systemic steroids are used in moderate-to-severe acute exacerbations of asthma and COPD to reduce airway inflammation rapidly. They shorten exacerbation duration and reduce treatment failure rates.
Methylprednisolone (Solu-Medrol)
IV: 40–125 mg q6h in acute exacerbations; 40 mg IV q24h in COPD exacerbation
Preferred IV route in acute severe asthma; monitor for hyperglycemia, fluid retention, mood changes
Prednisone
Oral: 40–60 mg/day for 5–14 days
First-line oral steroid for COPD and asthma exacerbations not requiring IV; equivalent efficacy to IV in non-severe presentations
Dexamethasone
IV/IM: 0.15–0.6 mg/kg (pediatric croup); adults: 10–20 mg single dose
Long half-life; used in croup (single dose), and as alternative to prednisone in asthma in some protocols
Mucolytics and Airway Clearance Medications
N-Acetylcysteine (NAC / Mucomyst)
Nebulization: 3–5 mL of 20% solution or 6–10 mL of 10% solution q4–6h
Breaks disulfide bonds in mucus glycoproteins, reducing viscosity. May cause bronchospasm — typically given with bronchodilator. Also used IV for acetaminophen toxicity.
Dornase Alfa (Pulmozyme)
Nebulization: 2.5 mg once daily
Rhyme DNase that cleaves extracellular DNA in CF sputum, dramatically reducing viscosity. Specific to cystic fibrosis. Requires specialized nebulizer (not compatible with standard jet neb).
Hypertonic Saline (3% or 7%)
Nebulization: 4 mL of 3% or 7% BID-QID
Osmotically draws water into airway lining, thinning mucus. Used in CF and bronchiectasis. Can cause bronchospasm — pretreat with bronchodilator. 7% more effective than 3% in CF.
Frequently Asked Questions
Why is albuterol combined with ipratropium in COPD exacerbations?
Albuterol (SABA) and ipratropium (SAMA) work via different mechanisms — beta-2 agonism vs. anticholinergic blockade. Combined, they provide complementary bronchodilation with additive effect and no increase in significant adverse events. The combination (DuoNeb nebulization or Combivent MDI) is guideline-recommended for moderate-to-severe COPD exacerbations.
What is the risk of systemic steroids in COPD patients?
Short-course systemic steroids (5–14 days) are beneficial in acute COPD exacerbations and are generally safe. Longer courses or frequent courses increase risk of hyperglycemia, osteoporosis, infection susceptibility, myopathy (including respiratory muscle weakness), and adrenal suppression. The shortest effective course is always preferred.
Can NAC (Mucomyst) cause bronchospasm?
Yes. NAC is known to cause bronchospasm, particularly in patients with reactive airways disease (asthma, COPD). Standard practice is to pretreat with a bronchodilator (usually albuterol) 15–30 minutes before NAC nebulization and to monitor the patient during treatment for signs of bronchospasm.
When is heliox used in respiratory therapy?
Heliox (helium-oxygen mixture, typically 70:30 or 80:20) reduces airflow turbulence because helium is less dense than nitrogen. It is used to decrease work of breathing in severe upper airway obstruction (croup, post-extubation stridor), severe asthma exacerbation, and as a bridge to other therapies. It does not treat the underlying disease and is a temporizing measure.
Summary
- SABAs (albuterol) are first-line rescue bronchodilators for acute bronchospasm
- Combining albuterol with ipratropium provides additive bronchodilation in COPD exacerbations
- ICS are the primary controller medications for persistent asthma — not for acute relief
- Short-course systemic steroids are guideline-recommended for moderate-to-severe COPD and asthma exacerbations
- Always pretreat with bronchodilator before NAC to reduce bronchospasm risk
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