Metered-dose Inhaler: How-to Guide

Nursing Knowledge

Metered-dose Inhaler: How-to Guide

Metered-dose inhalers (MDIs) play a big role in the administration of medications for respiratory conditions. These handheld devices deliver a specific dose of medication in aerosol form, making them a valuable tool in the clinical practice of nurses. This quick guide provides an overview of the types of metered-dose inhalers, advantages, and commonly used drugs.
Last updated: December 4, 2023

Table of contents

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. 


  • Convenient and easy to use
  • Non-breath activated
  • More cost effective than dry powder inhalers
  • Require no preparation


  • Patient coordination required
  • High pharyngeal deposition
  • Challenging to ascertain the remaining doses

Comparison: Types of inhalers 

Metered-dose inhalersDry powder inhalersSoft 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 usedTurn 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  

  1. Take off cap, shake inhaler, prime.
  2. Stand up or sit up straight.
  3. Breathe out completely and empty your lungs.
  4. Place mouthpiece on your mouth.
  5. Close lips to form a tight seal or use  2-finger space as directed.
  6. Start to breathe in, press down top of canister to release one “puff” of medicine.
  7. Continue to breathe in for 3–5 seconds.
  8. Hold your breath and count to 10.
  9. Take mouthpiece off your mouth and release your breath, rinse your mouth with water.
  10.  Put cap back on the inhaler.

Study tip: Mnemonic to remember the steps 


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

  1. Take off cap, shake inhaler, prime.
  2. Stand up or sit up straight, take cap off.
  3. Connect inhaler into chamber/spacer.
  4. Breathe out away from the device.
  5. Put the chamber mouthpiece into your mouth.
  6. Press inhaler once and breathe deep and steadily.
  7. Hold breath for 10 seconds, then breathe out slowly.
  8. Rinse your mouth with water.
  9. 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


Metered-dose Inhaler: How-to Guide

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Metered-dose inhalers are the most common type of inhaler.

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