Question 1 · Medium
A 70-year-old man with COPD and benign prostatic hyperplasia is started on a once-daily inhaled bronchodilator from a dry-powder device. Two weeks later he complains of a dry mouth and is brought to casualty with acute retention of urine. Which drug was most likely started?
- ASalmeterol
- BFormoterol
- CTiotropium
- DIndacaterol
Show answerHide answer
Answer: C · Tiotropium
Tiotropium is a long-acting muscarinic antagonist that blocks M3 receptors on airway smooth muscle; as a quaternary compound little is absorbed, but enough can reach the circulation to cause dry mouth, urinary retention in men with prostatic enlargement, and worsening of angle-closure glaucoma. LAMAs are a first-choice maintenance bronchodilator in COPD and reduce exacerbations. Patients are taught to keep the powder or mist away from the eyes.
- A: Salmeterol is a twice-daily beta2-agonist without anticholinergic effects.
- B: Formoterol is a beta2-agonist without anticholinergic effects.
- D: Indacaterol is a once-daily beta2-agonist; it causes tremor and palpitations, not retention.