What is a metered-dose inhaler?
Metered-dose inhalers are the most common type of inhalers. They use a press-and-breathe method, delivering a specific dose of a medication in aerosol form.
Pros
- Convenient and easy to use
- Non-breath activated
- More cost effective than dry powder inhalers
- Require no preparation
Cons
- Patient coordination required
- High pharyngeal deposition
- Challenging to ascertain the remaining doses
Comparison: Types of inhalers
| Metered-dose inhalers | Dry powder inhalers | Soft mist inhalers |
| Hold medication in pressurized canister → Propellant sends medication out of the mouthpiece. | Store medicine as a powder inside capsules that are activated when inhaler is ready to be used | Turn liquid medicine into low-velocity aerosol mist that can be slowly inhaled through mouth; no propellant used |
Which drugs are administered with metered-dose inhalers?
Commonly used drugs in metered-dose inhalers:
- SABAs
- Inhaled corticosteroids (ICs)
- Combination drugs: LABAs and ICs
How to use a metered-dose inhaler: 10–step instruction
- Take off cap, shake inhaler, prime.
- Stand up or sit up straight.
- Breathe out completely and empty your lungs.
- Place mouthpiece on your mouth.
- Close lips to form a tight seal or use 2-finger space as directed.
- Start to breathe in, press down top of canister to release one “puff” of medicine.
- Continue to breathe in for 3–5 seconds.
- Hold your breath and count to 10.
- Take mouthpiece off your mouth and release your breath, rinse your mouth with water.
- Put cap back on the inhaler.
Study tip: Mnemonic to remember the steps
SPORTT:
Shake well
Prime inhaler
Breathe out
Rest inhaler on mouth or use 2-finger spacing
Take deep breath and press
Ten seconds, hold breath
What is a metered-dose inhaler spacer?
A metered dose inhaler spacer is a device that improves the delivery of medications from a metered dose inhaler by slowing down and breaking up medicine particles, helping more medicine to reach the lungs. It’s often a tube-like structure that attaches to the inhaler. Spacers can be especially helpful for children, older adults, or anyone having difficulty coordinating inhalation with the activation of the metered-dose inhaler.
How to use a metered-dose inhaler with spacer
- Take off cap, shake inhaler, prime.
- Stand up or sit up straight, take cap off.
- Connect inhaler into chamber/spacer.
- Breathe out away from the device.
- Put the chamber mouthpiece into your mouth.
- Press inhaler once and breathe deep and steadily.
- Hold breath for 10 seconds, then breathe out slowly.
- Rinse your mouth with water.
- Put the cap back on the inhaler.
What are possible side effects of using metered-dose inhalers?
- Thrush (with corticosteroids)
- Mouth sores
- Hoarse voice
- Headache
- Shakiness
- Tachycardia
