Key Takeaways
- Short-acting beta-2 agonists (SABAs) like albuterol are the first-line rescue bronchodilators; onset 5-15 minutes, duration 4-6 hours
- Long-acting beta-2 agonists (LABAs) like salmeterol and formoterol are maintenance medications, NOT for acute rescue
- Anticholinergics (ipratropium, tiotropium) block muscarinic receptors to reduce bronchoconstriction and secretions
- Inhaled corticosteroids (ICS) like fluticasone and budesonide reduce airway inflammation; NOT for acute bronchospasm
- Systemic corticosteroids (methylprednisolone, prednisone) are used for acute asthma/COPD exacerbations
- Mucolytics: N-acetylcysteine (Mucomyst) breaks disulfide bonds in mucus; dornase alfa (Pulmozyme) for cystic fibrosis only
- Exogenous surfactant (Survanta, Curosurf, Infasurf) is administered via ET tube for neonatal RDS
- Neuromuscular blocking agents (cisatracurium, rocuronium) are used in refractory ARDS; always with concurrent sedation and analgesia
Respiratory Pharmacology
Pharmacology questions appear throughout the TMC exam, particularly in the Interventions domain. You must know the drug classes, individual medications, mechanisms of action, indications, contraindications, and common side effects for all major respiratory medications.
Bronchodilators
Short-Acting Beta-2 Agonists (SABAs) — Rescue Medications:
| Drug | Brand Name | Dose (SVN) | Dose (MDI) | Onset | Duration |
|---|---|---|---|---|---|
| Albuterol | ProAir, Ventolin | 2.5 mg in 3 mL NS | 2 puffs (90 mcg/puff) | 5-15 min | 4-6 hours |
| Levalbuterol | Xopenex | 0.63-1.25 mg | 2 puffs (45 mcg/puff) | 5-15 min | 6-8 hours |
- Mechanism: Stimulate beta-2 receptors on bronchial smooth muscle → relaxation → bronchodilation
- Indications: Acute bronchospasm, asthma, COPD exacerbation, exercise-induced bronchospasm
- Side effects: Tachycardia, tremors, hypokalemia, nervousness, palpitations
- Key point: Albuterol is the FIRST-LINE treatment for acute bronchospasm
Long-Acting Beta-2 Agonists (LABAs) — Maintenance Only:
| Drug | Brand Name | Onset | Duration |
|---|---|---|---|
| Salmeterol | Serevent | 30-60 min | 12 hours |
| Formoterol | Foradil, Perforomist | 5-15 min | 12 hours |
| Olodaterol | Striverdi | 5 min | 24 hours |
- NEVER use LABAs alone for asthma — FDA black box warning for increased risk of severe asthma exacerbations
- Always combined with ICS for asthma (e.g., fluticasone/salmeterol = Advair)
Anticholinergics (Muscarinic Antagonists):
| Drug | Type | Dose (SVN) | Duration |
|---|---|---|---|
| Ipratropium (Atrovent) | Short-acting (SAMA) | 0.5 mg | 4-6 hours |
| Tiotropium (Spiriva) | Long-acting (LAMA) | DPI: 18 mcg daily | 24 hours |
- Mechanism: Block muscarinic (M3) receptors → reduce bronchoconstriction and secretion production
- Side effects: Dry mouth, urinary retention, pupil dilation (if sprayed in eyes), tachycardia
- Contraindications: Narrow-angle glaucoma (nebulized form), urinary retention, allergy to atropine/soybeans/peanuts
- Key point: Often combined with albuterol (DuoNeb: albuterol + ipratropium) for acute COPD exacerbation
Anti-Inflammatory Agents
Inhaled Corticosteroids (ICS):
| Drug | Brand Name | Device |
|---|---|---|
| Fluticasone | Flovent | MDI, DPI |
| Budesonide | Pulmicort | SVN (Respules), DPI |
| Beclomethasone | QVAR | MDI |
| Mometasone | Asmanex | DPI |
- Mechanism: Reduce airway inflammation, edema, and mucus production
- NOT for acute bronchospasm — effects take days to weeks
- Side effects: Oral candidiasis (thrush), hoarseness, dysphonia
- Prevention: Rinse mouth and spit after each use; use spacer with MDI
Systemic Corticosteroids:
- Methylprednisolone (Solu-Medrol): IV for severe acute exacerbations
- Prednisone: Oral taper for moderate exacerbations
- Dexamethasone: Used for croup in children; COVID-19 in ventilated patients
- Side effects (long-term): Hyperglycemia, osteoporosis, adrenal suppression, immunosuppression, weight gain
Mucolytics and Secretion Management
| Drug | Brand Name | Mechanism | Indication |
|---|---|---|---|
| N-acetylcysteine (NAC) | Mucomyst | Breaks disulfide bonds in mucus glycoproteins | Thick secretions; also acetaminophen overdose antidote |
| Dornase alfa | Pulmozyme | Cleaves extracellular DNA in sputum | Cystic fibrosis ONLY (reduces viscosity of CF sputum) |
| Hypertonic saline (3-7%) | — | Osmotic effect draws water into airways | Sputum induction; CF airway clearance |
ICU Medications for Ventilated Patients
| Drug Class | Examples | Purpose |
|---|---|---|
| Sedatives | Propofol, midazolam, dexmedetomidine | Patient comfort, ventilator synchrony |
| Analgesics | Fentanyl, morphine, hydromorphone | Pain management (assess pain first, then sedate) |
| Neuromuscular blockers (NMBAs) | Cisatracurium, rocuronium, vecuronium | Refractory ARDS, facilitation of proning; MUST use with sedation |
| Vasopressors | Norepinephrine, vasopressin, epinephrine | Septic shock, hemodynamic instability |
| Surfactant | Beractant (Survanta), poractant (Curosurf), calfactant (Infasurf) | Neonatal RDS; administered via ET tube |
A patient presents to the emergency department with acute severe asthma (wheezing, SpO2 89%, peak flow 35% predicted). What is the FIRST-LINE bronchodilator treatment?
Which mucolytic agent is approved ONLY for use in cystic fibrosis patients?
A patient on an inhaled corticosteroid reports white patches on their tongue and palate. This is MOST likely caused by:
Match each respiratory medication to its drug class.
Match each item on the left with the correct item on the right
Why must neuromuscular blocking agents (NMBAs) ALWAYS be administered with concurrent sedation and analgesia?
Which of the following are common side effects of short-acting beta-2 agonists (SABAs) like albuterol? (Select all that apply)
Select all that apply
Which medication class carries an FDA black box warning against monotherapy use in asthma?
A COPD patient in the emergency department receives both albuterol AND ipratropium via nebulizer. This combination is appropriate because:
Exogenous surfactant therapy is indicated for which condition?