Final answer:
A metered-dose inhaler is a canister of pressurized medication that delivers a specified dose in aerosol form. It is particularly useful for providing fast-acting relief during an asthma attack.
Step-by-step explanation:
The feature of a metered-dose inhaler is that it is a canister that contains pressurized medication. This type of inhaler administers a specific amount of medication in aerosol form each time it is used, providing a consistent dose to the patient. Metered-dose inhalers are designed to be used during an asthma attack, delivering fast-acting drugs directly to the lungs.
For individuals with asthma, the choice of medication, including the strength and formulation, is determined by the condition's severity, frequency of attacks, and identified triggers. While metered-dose inhalers are effective for many patients, young children or those who find it difficult to use them may instead be prescribed medication through a nebulizer, which turns liquid medication into a fine mist that is easy to inhale.