What is the mechanism of action (MOA) of Ipratropium (Atrovent)?

Ipratropium (Atrovent) works by selectively blocking muscarinic receptors, which are a type of acetylcholine receptor found in various tissues including the lungs. This action leads to bronchodilation, making it easier for patients with respiratory conditions such as chronic obstructive pulmonary disease (COPD) or asthma to breathe. By blocking these receptors, ipratropium inhibits the effects of acetylcholine, a neurotransmitter that can cause bronchoconstriction when stimulated, thus helping to open the airways.

This mechanism is particularly beneficial in acute settings where rapid bronchodilation is needed. Ipratropium's targeted action on muscarinic receptors also contributes to its role in preventing mucus secretion in the airways, further aiding respiratory function. In contrast, options related to blocking beta receptors or stimulating adrenergic receptors pertain to different classes of medications, such as beta-agonists, which have a different action profile. Inhibition of histamine release is more associated with antihistamines and does not apply to ipratropium’s mechanism. This makes the selection of the correct mechanism of action clear, as it directly describes how ipratropium functions in the body.