Скачать или смотреть Ipratropium - Mechanism of action. Anticholinergic and Antimuscarinic

Kia ora team, let's talk about how Ipratropium causes bronchodilation and what does anticholinergic and antimuscarinic mean?

Ipratropium – Summary for Clinical Understanding
• Ipratropium is a bronchodilator. It works by inhibiting parasympathetic tone in the airways.
• It is an anticholinergic agent with predominantly antimuscarinic activity. It blocks muscarinic receptors, particularly M3 receptors, preventing acetylcholine from causing bronchoconstriction — resulting in vagal inhibition and bronchodilation.
• The parasympathetic nervous system governs "rest and digest" functions. At rest, bronchoconstriction is more efficient for:
o Ventilation-perfusion (V/Q) matching
o Conserving energy
o Protecting the lungs by reducing airflow and helping trap inhaled pathogens or particles
• This also enhances the effectiveness of the cough reflex and supports mucus clearance.
• The vagus nerve (cranial nerve X) wanders like a vagrant throughout the body. One of the places it innervates is the smooth muscle of the airways, where it releases acetylcholine. This binds to muscarinic receptors, triggering bronchoconstriction and mucus secretion.
• Ipratropium is anticholinergic and antimuscarinic. It blocks the muscarinic receptors, preventing acetylcholine (released from the vagus nerve) from:
o Stimulating airway smooth muscle → bronchodilation
o Stimulating goblet cells → mild reduction in mucus production
• It does not act on β2 receptors, unlike salbutamol, which directly stimulates β2 adrenergic receptors to cause bronchodilation.

Happy studying