Ipratropium Bromide duration of action is typically:

• A. 4-6 hours
• B. 1-2 hours
• C. 8-12 hours
• D. 24 hours

Answer: (A)

Ipratropium bromide is a short-acting inhaled anticholinergic bronchodilator, so its effects last about 4–6 hours. It works by blocking muscarinic receptors in the airways, reducing vagal-induced bronchoconstriction and helping to open the airways. Because it’s a quaternary ammonium compound, it’s mainly active in the lungs with limited systemic absorption, which aligns with a moderate duration rather than a long one. In clinical practice, this means ipratropium is given repeatedly every 4–6 hours as needed for acute bronchospasm or COPD management.

Durations like 1–2 hours are shorter than typical for ipratropium, while 8–12 hours or 24 hours describe long-acting agents (such as tiotropium), not ipratropium.