Pharmacology · patient case question
What is the mechanism of action of albuterol?
Patient case: Reviewing a long medication list
Patient: Female, 55 years old
Chief Complaint: Presents for a comprehensive examination.
Background: Graves disease, hypertension, asthma. She carries a naloxone kit because a family member has opioid use disorder.
Medications: Propylthiouracil · lisinopril · albuterol inhaler · naloxone (rescue kit)
Vital Signs: BP 132/84 mmHg · HR 84 bpm · RR 16
Show answer and explanation
Correct answer: C. Beta-2 adrenergic receptor agonist
- A. Muscarinic antagonism is ipratropium and tiotropium, used more in COPD than in acute asthma.
- B. Phosphodiesterase inhibition describes theophylline, an older bronchodilator now rarely used because of its narrow therapeutic index.
- C. CORRECT. Albuterol (salbutamol) is a short-acting selective BETA-2 AGONIST. Beta-2 stimulation raises cyclic AMP in bronchial smooth muscle and relaxes it, giving relief within minutes — this is the rescue inhaler. Its selectivity is relative rather than absolute, so at high doses it spills over to beta-1 and produces tachycardia and tremor.
- D. Leukotriene receptor antagonism is montelukast — a controller, not a rescue medication.