What is a Metered Dose Inhaler (MDI) and how does it work?

Here's how it works:

1. When you press the canister, a propellant vaporizes, creating a high-pressure burst that forces the drug out through a nozzle.
2. This rapid expansion forms a fine mist (aerosol) with tiny particles (1-5 μm) that can reach your lower airways.
3. For effective use, you need to coordinate pressing the inhaler with a slow, deep inhalation. Shaking the inhaler for 5 seconds before use ensures a uniform dose, especially for suspensions.
4. After inhaling, holding your breath for 5-10 seconds allows the medicine particles to settle in your lungs, ensuring more drug reaches the alveoli.