What is a handheld inhaler primarily used for?

A handheld inhaler is primarily used as a device that delivers medication directly to the lungs. This method of administration is particularly effective for respiratory conditions such as asthma or chronic obstructive pulmonary disease (COPD). Inhalers allow for medication to act quickly where it is needed most—within the airways and lung tissues—by bypassing the digestive system and bloodstream. Medications delivered through inhalers may include bronchodilators, corticosteroids, or combination products that help open the airways and reduce inflammation, providing swift relief from respiratory symptoms.

The other options represent devices with distinct functions that do not relate to the primary purpose of a handheld inhaler. Monitoring heart rate, increasing blood sugar levels, and administering injections all pertain to different medical interventions that target different aspects of health and treatment.