Any metered-inhaler has three parts into it: a canister, a metering valve and an actuator or mouthpiece. The function of this mouthpiece or actuation is to allow the patient to operate the inhaler and directs the medicine into the patient’s lungs.

Poor coordination of canister actuation and inspiration often prevents adequate metered-dose inhaler (MDI) usage by patients, perhaps especially among the elderly. Breath-actuated inhalers (BAI) have been developed to prevent this problem.

The actuation comes with every inhaler; such as,

Ventolin inhaler contains 100 mcg of Salbutamol sulphate per actuation; Atrovent inhaler contains 20 micrograms/actuation, Serevent (Salmeterol) is available in 25 micrograms per actuation inhaler etc.