Foundations

How the Airways Work — and Why We Inhale the Drug

Almost every drug in this section is breathed in rather than swallowed, and that isn't an accident — it's the single most important idea in respiratory pharmacology. Understand what narrows an airway and why we deliver the drug straight to the lungs, and every inhaler, bronchodilator and steroid that follows will make immediate sense.

Inhalers & Devices: Getting the Drug to the Lungs

The best asthma drug in the world is useless if it never reaches the lungs — and studies show a large fraction of patients use their inhaler wrong. This is the most practical topic in respiratory medicine: knowing the device types, why a spacer helps so much, and the small habits that make the difference between a drug that works and one that doesn't.