How Do Inhalers Work?

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Asthma is a chronic illness caused by inflammation of the airways of the lungs (bronchioles). It causes symptoms such as wheezing, shortness of breath, and coughing. Asthma is often treated using inhaled medications, which reduce inflammation to improve the flow of oxygen.

Inhalers are used during an asthma attack to expand the airways, allowing for the flow of oxygen. People with asthma should carry a rescue inhaler with them at all times to stop an acute asthma attack and prevent serious complications.

This article discusses the different types of inhalers, how they work, and the proper technique for using them.

A man with glasses using a rescue inhaler in the living room.

MixMedia / Getty Images

Types of Inhalers

There are several different types of inhalers used to treat asthma.

Metered Dose Inhalers

Metered dose inhalers (MDIs) are small, pressurized metal containers with a plastic mouthpiece, meant for handheld use. Asthma medication is dispensed in a measured dose.

MDIs are very common because they are easy to use and carry.


A nebulizer is a device that changes a liquid medication into an aerosol so that it can be inhaled, relieving symptoms faster.

While nebulizers are frequently used to deliver asthma medications, they are not as convenient to carry as an MDI because they require electricity. This makes them more difficult to use for a sudden asthma attack.

Dry Powder Inhaler

A dry powder inhaler (DPI) is a device used to deliver asthma medication in the form of a dry powder. The device is not under pressure in the way that an MDI is, so it does not "push" the medication into your lungs. Rather, you must inhale deeply to get the medication.

Advair Diskus is a common brand of DPI.

How Do Inhalers Work?

Inhalers deliver medication directly to the lungs. These medications typically work to either reduce inflammation in the airways or to dilate the airways.

Medications that dilate the airways are meant to enlarge their diameter to increase oxygen flow. These are called bronchodilators. In this manner, inhalers can sometimes prevent future asthma attacks (usually with medications that reduce inflammation) or treat an acute asthma attack.

The Right Technique

Metered Dose Inhaler

MDIs can be used with or without a special holding chamber, sometimes called a spacer.

Without a spacer:

  1. Remove the plastic cap of the inhaler.
  2. Shake the inhaler.
  3. Some inhalers need to be primed, which consists of depressing the canister and releasing a few puffs of the medication into the air prior to use.
  4. Put the mouthpiece in your mouth and seal your lips around it.
  5. Begin to inhale slowly and deeply while depressing the canister one time. Continue to breath in for approximately five seconds.
  6. Hold your breath for approximately 10 seconds before exhaling.

With a spacer:

  1. Remove the plastic cap of the inhaler.
  2. Shake the inhaler.
  3. If necessary, prime the inhaler. If you are unsure whether your inhaler needs to be primed, this information should be located in the packet insert that came with your inhaler.
  4. Connect the spacer to the mouthpiece.
  5. Exhale.
  6. Put the mouthpiece of the spacer up to your mouth and seal your lips around it. Keep your chin up.
  7. Begin to inhale slowly while depressing the canister to release one puff of medication.
  8. Hold your breath for approximately 10 seconds before puckering your lips and exhaling slowly.
  9. Additional steps may be necessary depending on what type of medication you are using. If you are using a rescue inhaler (beta agonist) you should wait for one minute before taking another puff. If you are using a corticosteroid medication, you should rinse your mouth out after use. If you are unsure, consult your healthcare provider or pharmacist.


Using a nebulizer may be a bit more complicated, depending on the specific type of equipment you own.

We recommend you become familiar with your air compressor and how to run it by reading the manual that comes with the device. You should also familiarize yourself with all of the nebulizer parts.

Be sure to wash your hands before handling your equipment and medications, and always keep your equipment clean. Then do the following:

  1. Connect the hose to the air compressor.
  2. Fill the medication cup, then connect it to the hose and mouthpiece.
  3. Put the mouthpiece in between your teeth and seal your lips around it. If you are using a face mask instead of a mouthpiece, simply put the mask on.
  4. If you are using a mouthpiece, you will need to breathe through your mouth rather than your nose until the medication is completely gone. If you are using a mask, breathe normally.
  5. When the medication is gone, turn off the equipment and clean it properly.

Dry Powder Inhaler

  1. If you have a multidose inhaler, click the device to ready it for use. If you have a single-dose inhaler, you will need to drop the capsule of medication into the chamber on the device.
  2. Exhale deeply.
  3. Hold the inhaler like a sandwich and put the mouthpiece in between your teeth, sealing your lips around it.
  4. Take a deep, fast breath. Hold the breath for approximately 10 seconds before exhaling.
  5. If you are using a single-dose inhaler, check the chamber to make sure the entire dose is gone.
  6. Close the device and store in an area that is both clean and dry.

When Should You Use an Inhaler?

Some inhalers are used to prevent asthma attacks rather than treat an acute attack. These inhalers are used at regular intervals. Rescue inhalers are used to treat an acute asthma attack.

Individuals who have been diagnosed with asthma should have something called an asthma action plan, which outlines specific steps that should be taken to prevent and treat an asthma attack. This includes when to use your rescue inhaler.

Most asthmatics will need to use their rescue inhaler as soon as they experience symptoms, such as shortness of breath or wheezing.

Potential Side Effects

While the exact side effects depend on the specific medication you are inhaling, most rescue inhalers can cause side effects such as:

Overuse of your asthma medications may exacerbate (worsen) side effects. Use your medications only as prescribed, follow your asthma action plan, and contact your healthcare provider or pharmacist with any questions or concerns to avoid this.


Inhalers are small devices that expand the airways, which allows for the flow of oxygen. They are used to treat asthma. The main types of inhalers include metered dose inhalers, nebulizers, and dry powder inhalers. Each type is different, so be sure to carefully read the instructions of whatever inhaler you use to treat your asthma.

A Word From Verywell

The correct use of inhalers is an important component of managing asthma and improving your quality of life. Knowing how to use your inhaler properly can give you peace of mind in the event of an asthma attack. If you are unsure how to use your inhaler, discuss with your healthcare provider or pharmacist.

Frequently Asked Questions

  • How fast do inhalers work?

    This may depend on a variety of factors, including the specific medication inhaled as well as the way your body metabolizes it. Maintenance inhalers that address underlying inflammation and are taken at regular intervals do not work as quickly and may require many doses before you notice improvement. Rescue inhalers typically work very fast, within minutes after the dose is finished.

  • What do inhalers contain?

    Inhalers can contain many different medications, but they typically fall into specific classes of medications including corticosteroids or beta agonists.

  • How do you use a Ventolin inhaler?

    Ventolin (albuterol) is a rescue inhaler that is usually administered via metered dose inhaler (MDI). Follow the instructions in this article for using an MDI.

  • How long after using an inhaler can you drink water?

    If you are using a corticosteroid inhaler, you should rinse your mouth with water and spit the water out right after use. However, after you have rinsed your mouth out, you can drink normally.

  • What happens if you don’t rinse your mouth after using inhaler?

    The inside of your mouth may become irritated by exposure to the medication, or you may absorb the medication into your blood stream. Rinsing your mouth after also decreases the chance of developing oral thrush (a type of fungal infection).

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. American Academy of Family Physicians. How to use a metered dose inhaler.

  2. MedlinePlus. How to use an inhaler - with spacer.

  3. MedlinePlus. How to use a nebulizer.

  4. Allergy and Asthma Network. How to use a dry powder inhaler.

  5. National Health Service. Steroid inhalers.

By Kristin Hayes, RN
Kristin Hayes, RN, is a registered nurse specializing in ear, nose, and throat disorders for both adults and children.