What is the purpose of using a spacer with a metered dose inhaler (MDI)?

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Last updated: July 6, 2025View editorial policy

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From the Guidelines

Using a spacer with a metered dose inhaler (MDI) is crucial to improve medication delivery to the lungs and reduce side effects. The spacer acts as a holding chamber that captures the medication spray after it's released from the inhaler, allowing the user to inhale the medication more slowly and effectively. This is particularly beneficial because many patients struggle with proper MDI technique, often failing to coordinate the press of the inhaler with their inhalation. The spacer eliminates this timing issue by holding the medication particles in suspension until the patient inhales.

According to the 2024 American Heart Association and American Red Cross guidelines for first aid 1, when used with a metered dose inhaler, spacer devices improve the delivery of bronchodilator medications to the lungs. Additionally, the guidelines suggest that inhalers with spacer devices provide clinical effectiveness equal to that of nebulizer machines, including in community settings.

Some key benefits of using a spacer with an MDI include:

  • Improving medication delivery to the lungs
  • Reducing side effects like oral thrush from inhaled corticosteroids
  • Decreasing systemic absorption
  • Eliminating the timing issue associated with coordinating the press of the inhaler with inhalation
  • Increasing the amount of medication reaching the airways, sometimes delivering 2-4 times more medication to the lungs compared to using an MDI alone

It's also worth noting that improvised spacers made with a 500-mL plastic cold drink bottle or a 150-mL disposable paper cup appear to provide drug delivery similar to that achieved with commercial spacer devices 1. Furthermore, the 2024 guidelines recommend using either an inhaler with a spacer or a nebulizer when assisting a person with asthma to use their own inhaled bronchodilator medication, in preference to using an inhaler alone 1.

In terms of specific patient populations, spacers are especially recommended for children, elderly patients, and anyone who finds it difficult to use an MDI correctly. The expert panel report 3 (EPR-3) guidelines for the diagnosis and management of asthma also suggest that spacers or valve-holding chambers (VHCs) should be used with nonbreath-activated metered-dose inhalers (MDIs) to reduce local side effects 1.

Overall, the use of a spacer with an MDI is a simple and effective way to improve medication delivery and reduce side effects, and it is a recommended practice in the management of asthma.

From the Research

Purpose of Using a Spacer with a Metered Dose Inhaler (MDI)

The primary purpose of using a spacer with a metered dose inhaler (MDI) is to:

  • Improve drug delivery to the lungs by reducing oropharyngeal deposition and increasing lung deposition 2, 3, 4
  • Minimize coordination difficulties between inhalation and actuation 2, 3, 4
  • Enhance the clinical effect of inhaled medications, especially in patients who are unable to use a pMDI properly 3, 5
  • Allow for the reduction of maintenance dosages of bronchodilators and corticosteroids 2, 3
  • Provide a viable alternative to nebulizers for delivering large bronchodilator doses in patients with severe acute asthma or chronic obstructive pulmonary disease 2, 3

Benefits of Using a Spacer

The benefits of using a spacer include:

  • Improved inhaler technique in patients using a pMDI 4
  • Reduced local side effects such as oral candidiasis and dysphonia 6
  • Increased response to beta-adrenergic bronchodilators, even in patients with correct inhalation technique 3
  • Ability to deliver high doses of inhaled corticosteroids with a lower maintenance dose 3

Recommended Use of Spacers

Spacers are recommended for:

  • Young children and the elderly to effectively deliver medication to the airways 4
  • Patients with severe acute asthma or chronic obstructive pulmonary disease as a viable alternative to nebulizers 2, 3
  • Delivering high doses of inhaled corticosteroids with a lower maintenance dose 3

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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