What is the correct way to use a metered-dose inhaler (MDI)?

Correct Technique for Using a Metered-Dose Inhaler (MDI)

For patients ≥5 years old using a standard MDI, the optimal technique involves actuating the device during a slow, deep inhalation (30 L/min or 3-5 seconds) followed by a 10-second breath hold, and a spacer or valved holding chamber (VHC) must be used for all children <4 years old and for any patient who cannot coordinate actuation with inhalation. 1

Step-by-Step MDI Technique

Preparation

• Shake the inhaler before each use to ensure proper medication mixing 2
• Remove the cap and check that the mouthpiece is clean 1
• Prime the inhaler if it's new or hasn't been used recently (follow manufacturer instructions) 2

Positioning

• Position the MDI correctly using either:
  • Closed-mouth technique: Place the mouthpiece between your lips and teeth, creating a tight seal 1
  • Open-mouth technique: Hold the MDI 2 inches (two finger-widths) away from your open mouth, which enhances lung delivery under laboratory conditions 1

Inhalation Technique

• Exhale completely to residual volume before actuation 1
• Begin a slow, deep inhalation at 30 L/min (taking 3-5 seconds to inhale fully) 1
• Actuate the canister once at the very start of your inhalation, not before or during mid-inhalation 1
• Continue inhaling slowly and deeply after actuation—do not stop inhaling when you press the canister 1
• Hold your breath for 10 seconds after completing the full inhalation to allow medication deposition in the airways 1

After Use

• Wait 10-15 seconds between puffs if multiple puffs are prescribed; longer intervals offer no additional benefit 2
• Rinse your mouth and spit after using inhaled corticosteroids to reduce systemic absorption and prevent oral thrush 1, 2

When to Use a Spacer or Valved Holding Chamber

A spacer/VHC is mandatory for:

• All children <4 years old, as they cannot generate sufficient inspiratory flow or coordinate actuation 1
• Patients who cannot coordinate actuation with inhalation 1
• Elderly patients with weak fingers, poor coordination, or cognitive impairment 2
• All patients using inhaled corticosteroids to reduce local side effects 1

Spacer/VHC Technique

• Actuate only once into the spacer per inhalation—multiple actuations dramatically reduce drug delivery 1, 3
• Begin slow, deep inhalation immediately after actuation (within seconds, not minutes) 1
• Inhale slowly over 3-5 seconds at 30 L/min 1
• Hold breath for 10 seconds after completing inhalation 1

Spacer Maintenance

• Rinse plastic VHCs once monthly with low-concentration liquid household dishwashing detergent (1:5000 dilution or drops per cup of water) 1
• Let drip dry to reduce static charge and enhance drug delivery 1

Common Errors to Avoid

Critical pitfalls that reduce medication delivery:

• Stopping inhalation at actuation instead of continuing to inhale slowly and deeply 1
• Inhaling too rapidly instead of maintaining a slow rate of 30 L/min 1
• Not holding breath for 10 seconds after inhalation 1
• Actuating multiple times into a spacer before inhaling, which significantly reduces drug delivery 1, 3
• Poor coordination between actuation and inhalation, which is the most common problem with MDI use 4

Verification and Training

Physicians must observe and regularly review patients' inhaler technique because many if not most patients have difficulty with proper inhalation technique 2. Incorrect MDI use is directly associated with poor asthma control and increased need for systemic steroids 5. Patients should demonstrate correct technique before being prescribed an MDI, and those unable to use the device correctly should be prescribed a spacer or an alternative device such as a breath-actuated inhaler 5.

Repetitive training improves technique—patients trained 3 times have significantly higher rates of correct use 6. The first treatment should be given under supervision 2.

Alternative Devices for Patients Unable to Use Standard MDI

If a patient cannot master standard MDI technique despite proper instruction, consider:

• MDI with spacer and tight-fitting face mask 2
• Breath-activated inhaler 2
• Dry powder inhaler 2
• Nebulizer as a last resort 2