What is an important technique for using a metered dose inhaler (MDI)?

The correct answer underscores the significance of shaking the metered dose inhaler (MDI) before use to ensure the medication is properly mixed and delivered in a consistent dose. Many MDIs contain a suspension or solution that requires thorough mixing to ensure that each puff delivers the appropriate amount of medication, especially if the inhaler has been inactive for a period of time. By shaking the inhaler, the patient can help to ensure that the aerosolized medication is evenly distributed and ready for optimal delivery during inhalation.

While it is important to exhale completely before inhaling to ensure that the lungs can take in the full dose of medication, this technique alone does not address the need to prepare the inhaler itself. Taking a rapid, short breath in is not ideal for MDI use; a slow and deep inhalation is recommended for proper medication deposition in the lungs. Pressing the canister before starting to inhale also does not prepare the medication, as it is vital to synchronize inhalation with the actuation of the canister to maximize drug delivery. Thus, shaking the inhaler is key to ensuring that the medication is effectively delivered when the patient inhales.