Hydrofluoroalkane inhalers(using Hfa-134A Pharma Grade as propellant) or HFAs (formerly called meter does inhalers) provide the drug through a small, handheld aerosol canister. They work like a spray can. You push the inhaler, it sprays out the medicine, and you breathe it in. A tube-like gadget called a spacer can help kids or people with trouble breathing use an HFA more easily.
What do we need to Know about Metered-Dose Inhalers and the HFA Propellant
There are a number of ways to deliver inhaled medication. They include:
Metered-dose inhaler (MDI)
Metered-dose inhaler with spacer/holding chamber
Dry powder devices
This information will focus on the metered-dose inhalers. The metered-dose inhalers contain an HFA propellant (hydrofluoroalkane propellant) propellant. The table below is a current list of metered-dose inhalers with the HFA propellant.