Asthma inhalers: The 3 device types explained

Asthma inhalers are small, hand-held devices used to deliver asthma medication. They help to prevent and relieve asthma symptoms by delivering medication to the airways and lungs. Three different types of asthma inhalers are available including:

• Metered dose inhalers
• Dry powder inhalers
• Soft mist inhalers

To get the maximum benefit out of your inhaler it’s important to know how to use and care for it correctly. Talk to your healthcare provider about what type of inhaler is right for you. Read on to learn more about the three different inhaler device types.

Metered-dose inhalers

Metered dose inhalers (MDIs) are also known as aerosol or puffer inhalers. MDIs consist of a small pressurized canister containing the medication, which sits inside a plastic case. Pressing the button on top of the canister releases a set dose of medicine through the mouthpiece (actuator) of the inhaler, which the patient then breathes in as it is puffed out.

To receive the maximum benefit from an MDI, it’s recommended that they be used with another device called a spacer or holding chamber. A spacer is a specially designed plastic tube that is attached to the mouthpiece of an inhaler. The medication is puffed into the spacer and the patient breathes it in via a mouthpiece on the other end of the spacer.

Using a spacer has a number of advantages. A spacer:

• Enables more medication to be delivered to the lungs, which is useful when trying to relieve asthma symptoms
• Helps to prevent the oral thrush caused by preventer medication by reducing the amount of medication that touches the back of the throat
• Makes an MDI easier to use because the patient doesn’t have to be able to coordinate breathing in the medication at the exact moment they press the button on the inhaler
• Can be used during an asthma attack if a nebulizer is not available

How to use a metered-dose inhaler

• Prime your inhaler. Priming your inhaler is required to make sure that the dosing chamber of the inhaler has the right amount of medication available to dispense. It is necessary to prime an inhaler the very first time you use it and if it hasn’t been used for several days or weeks.
  Remove the cap, shake the inhaler and spray it into the air. Check the instructions that come with your inhaler to see how many sprays are needed.
• For regular use, begin by removing the cap from the mouthpiece.
• Shake the inhaler to mix the medication and propellant.
• While standing or sitting upright, tilt your head back and gently breathe all the way out.
• Hold the inhaler upright and insert the mouthpiece into your mouth. Make sure your lips seal firmly around the mouthpiece.
• Begin taking a slow deep breath and at the same time release a dose of medication by pressing down once on the top of the canister.
• Continue breathing in until you have taken a full breath.
• Remove the MDI from your mouth and hold your breath for ten seconds.
• Breathe out gently through your nose.
• If a second dose is required then repeat the steps above.
• If using a corticosteroid preventer inhaler, rinse your mouth out or clean your teeth to help prevent thrush.

How to clean your metered-dose inhaler

Clean your MDI once a week, or as directed, to make sure it doesn’t become blocked. Start by removing the cap and canister. Do not put the canister in water. Rinse the plastic mouthpiece and cap in warm water for about 30 seconds, if this is recommended for your particular MDI. Some recommend cleaning with a dry cloth or tissue only. Shake the mouthpiece and cap to remove excess water and leave out to air dry. Once dry, replace the metal canister and cap and it’s ready to use.

Dry powder inhalers

Dry powder inhalers (DPIs) contain the medicine in the form of a dry powder, with no propellant or added carrier like MDIs have. They may contain traces of lactose, however, which can affect those unable to tolerate it.

DPIs are also called breath activated inhalers, because they are designed to release a dose of medication as you take a deep, fast breath in. This means that they do not require the hand-breath coordination needed to use an MDI, but it can also mean that they are difficult to use during an asthma flare up if the patient is unable to breathe in forcefully enough. You won’t necessarily taste or feel the powder when you use this type of inhaler.

How to use a dry powder inhaler

• Prime your inhaler. Read the instructions for use that come with your inhaler to find out how to load a dose of medication. Some DPIs require a powder-filled capsule to be loaded for each use, while others have pre-loaded doses of powder. DPIs with pre-loaded powder will have an indicator to show how many doses are left.
  Do not load a dose until you are ready to use it or shake your inhaler. Do not try to inhale the contents of a capsule without the appropriate device.
• For regular use, stand or sit up straight and empty all the air out of your lungs by breathing out completely.
• Put the mouthpiece up to your mouth and form a tight seal around it with your lips. The mouthpiece should be pointed up or held horizontally. Do not use a spacer with a DPI.
• Breathe in quickly and forcefully through the mouthpiece, then remove the inhaler from your mouth and hold your breath for 10 seconds before slowly exhaling.
• If using a capsule device check that there is no powder left in the capsule. If powder is still visible then close the device and repeat the steps above to inhale the remainder of the powder.
• If a second dose is required, load a new dose and repeat the steps above.
• Close the device and store in a dry place.
• Rinse your mouth out if instructed to do so.

How to clean you dry powder inhaler

To clean the mouthpiece of your DPI, regularly wipe it with a dry cloth. Do not wash your DPI in water.

Soft mist inhalers

Soft mist inhalers (SMIs) are a newer type of inhaler and contain the medication in a liquid form. The liquid is converted into a fine mist that is inhaled by a compressed spring in the inhaler.

Like DPIs, the SMIs do not contain a propellant. They do, however, require the same hand-breath coordination required to use an MDI. SMIs are thought to deposit less medication on the back of the throat, meaning that more of it reaches the lungs.

• Prepare your inhaler. SMIs need to be prepared for use the first time you use them. Read the instructions for use that come with your SMI. To prepare your SMI:
  • Remove the clear base. To remove the clear base, keep the cap closed and press the safety catch while pulling off the clear base with the other hand.
  • Insert the narrow end of the cartridge into the inhaler. Put the inhaler on a firm surface, such as a bench or table, and push down firmly on the inhaler until the cartridge clicks into place.
  • Track the cartridge by marking the checkbox on the inhaler’s label then click the clear base back into place.
  • With the cap still closed, turn the clear base half a turn in the same direction as the arrows on the label until the base clicks.
  • Fully open the cap until it snaps into place.
• Prime your inhaler. To prime the inhaler, point the inhaler towards the ground and press the dose release button before closing the cap. With the cap closed, turn the clear base half a turn in the same direction as the arrows on the label until the base clicks. Then fully open the cap and once again point the inhaler at the ground and press the dose-release button. Repeat this process until a cloud of mist is visible. Once a cloud is visible, repeat the process three more times. The SMI is then ready to use with 60 puffs (30 doses) available.
• For regular use, load one puff on medication by keeping the cap closed and turning the clear base half a turn in the same direction as the arrows on the label until the base clicks.
• Open the cap until it snaps fully open.
• Stand or sit up straight and breathe out slowly and fully. Do not breathe out over your inhaler.
• Seal your lips around the mouthpiece of the inhaler without covering the air vents on the sides and point the inhaler towards the back of your throat.
• Begin taking a slow, deep breath in through the mouthpiece and press the dose-release button. Continue to breathe in slowly for as long as is comfortable, then hold your breath for 10 seconds before slowing exhaling.
• Repeat the process to deliver the second puff as directed (two puffs equals one dose).
• Close the cap and store your inhaler.
• SMIs have a dose indicator to show how many doses are left. When a white arrow on a red background appears in the dose indicator window, the cartridge is empty and needs to be replaced. Turn the clear base to loosen the cartridge so that it can be pulled from the inhaler and a new one inserted.

How to clean you soft mist inhaler

Once a week clean the mouthpiece of your SMI, including the metal part on the inside of the mouthpiece, with a tissue or damp cloth. Minor discoloration of the mouthpiece does not affect how well your inhaler works.