7.2 : Inhaled Medications

Inhaled medications are crucial for managing chronic obstructive pulmonary disease (COPD) and asthma. They are essential for effective treatment and control, ensuring optimal respiratory health and well-being. Inhaled medication delivers drugs directly to the lungs, providing a rapid onset of action and reducing systemic side effects compared to oral or injectable medications. Three primary types of inhalation devices are used to administer these medications: nebulizers, metered-dose inhalers (MDIs), and dry-powder inhalers (DPIs).

Nebulizers modify liquid medication into a fine mist for inhalation, ensuring that the drug reaches and is effectively absorbed in the lower respiratory tract. They are typically easy to use, making them suitable for individuals with severe asthma or those who struggle with manually operated inhalers. Common nebulized agents include bronchodilators like albuterol and anticholinergics like ipratropium.

Metered-dose inhalers (MDIs) are portable devices that dispense a precise medication dosage with every canister press. These inhalers require the user to coordinate their breath with the activation of the device, which can be challenging for some patients, especially pediatric patients. To aid in this process, many MDIs can be used with a spacer or extender device, which acts as a medication reservoir, simplifying administration and making the dose more predictable. MDIs are commonly used for various drugs, including bronchodilators and corticosteroids.

Dry-powder inhalers, or DPIs, contain a dry, powdered medication activated by the user's breath. They eliminate the need to coordinate activation and inhalation, making DPIs easier to use than MDIs for some patients. However, DPIs have a few limitations. The medication can clump if exposed to humidity, and patients with a low Forced Expiratory Volume in one second (FEV1) — a measure of how much air a person can exhale in one second — may struggle to inhale the medicine.