Short-acting muscarinic antagonists (SAMAs) are used to manage chronic obstructive pulmonary disease (COPD). They work by blocking the action of acetylcholine, a chemical that causes muscles around the airways to tighten. This makes it easier for you to breathe. SAMAs are available as inhalers and nebulizer solutions. Examples include ipratropium inhaler (Atrovent HFA) and ipratropium nebulizer solution. You can discuss with your healthcare team which option might be right for you.