Medicine & USMLE


Respiratory Drugs
  1. Beta-2 Agonists (Albuterol, Salmeterol)
  2. Cromolyn
  3. Montelukast
  4. Guaifenesin
  5. Ephedrine / Phenylephrine
  6. Acetylcysteine
  7. Theophylline


Acetylcysteine is a medication with differing effects depending on how it is administered. When given through inhalation, it can be used to thin respiratory secretions to treat pulmonary congestion.  When given orally or through an IV, it is used to treat acetaminophen overdose. One side effect seen with taking acetylcysteine through inhalation is bronchospasm, so be cautious when giving acetylcysteine to patients who have asthma.

Key Points

  • Acetylcysteine (Mucomyst)
    • Mechanism
      • Mucolytic
        • Thins respiratory secretions to promote flow
    • Clinical Use
      • Pulmonary Congestion
        • Given via inhalation
        • Acute and chronic pulmonary conditions that have large amount of secretions
        • Cystic fibrosis
      • Acetaminophen Overdose
        • Given orally or via IV
        • Acetylcysteine has an odor that smells like rotten eggs. This is normal and expected. When giving orally, it is usually better tolerated when diluted in a flavored beverage
    • Side Effects and Adverse Reactions
      • Bronchospasm
        • Use with caution in patients with asthma
      • Aspiration
      • Dizziness
      • Drowsiness
      • Hypotension
      • Tachycardia
      • Hepatotoxicity