What is the first step in using a metered-dose inhaler (MDI) correctly?

Shaking the metered-dose inhaler (MDI) is a critical first step because it ensures that the medication inside the canister is properly mixed and ready for delivery. Many MDIs contain a propellant that can settle at the bottom while sitting unused. By shaking the inhaler, you ensure that the medication is aerosolized correctly, which allows for more effective and even dosing when it's dispensed.

This initial step is essential because if the inhaler is not shaken, the patient may receive a dose that is not representative of the intended medication formulation, leading to reduced efficacy. The other steps, such as inhaling deeply, placing the inhaler in the mouth, or pressing the inhaler, are important but should be done following the correct preparation of the inhaler with shaking. Therefore, starting with this step lays the foundation for the effective use of the inhaler.