When using a metered dose inhaler, what should be done immediately before inhalation?

Before using a metered dose inhaler (MDI), it is essential to shake the inhaler and remove the cap immediately before inhalation. Shaking the inhaler ensures that the medication is well mixed and that the proper dose is delivered. Many MDIs contain suspensions, and the medicine can separate over time, so shaking redistributes it effectively.

Removing the cap is also vital to ensure that the mouthpiece is clear and ready for use. This step helps avoid introducing any blockages that could interfere with the delivery of the medication.

While other actions may be important in certain contexts—like using a spacer or checking expiration dates—shaking the inhaler and removing the cap are the immediate preparatory steps for ensuring that a patient can receive the intended dose effectively. Exhaling forcefully is typically advised just before inhalation to help clear the airways, but it comes after the initial preparatory steps of shaking and removing the cap.