Which of the following is a short-acting bronchodilator?

• A. Ipratropium bromide
• B. Tiotropium
• C. Salmeterol
• D. Theophylline

Answer: (A)

Quick relief of bronchospasm is provided by short-acting bronchodilators. Ipratropium bromide is a short-acting anticholinergic bronchodilator that works by blocking acetylcholine receptors in the airways, which reduces bronchoconstriction and opens the airways rapidly for a few hours. Tiotropium and salmeterol are long-acting agents used for maintenance, not immediate relief. Theophylline is an older drug with variable onset and not used as a quick-acting rescue medication. So ipratropium bromide is the appropriate short-acting option.