Pressurised Metered Dose Inhalers

What is a Metered Dose Inhaler?

A metered dose inhaler (MDI), also known as an aerosol inhaler or puffer, is a device for delivering medicine directly into the lungs. It consists of a pressurised metal canister containing a solution or suspension of medicine, placed within a plastic case with a mouthpiece. When the canister is pushed down, a valve delivers a measured dose of medicine in a fine mist. This is inhaled into the lungs via the mouthpiece. Using an inhaler delivers your medicine directly into the lungs where it is needed.

Using such an inhaler device can require considerable coordination, but it is important that the correct technique is used. If not, you won’t fully inhale the correct dose of your medicine. This not only makes it less effective, but may also result in the medicine ending up in your mouth or throat, where it can cause side effects such as throat irritation.

 

How to Use an MDI

1. Sit up straight or stand up and lift the chin to open the airways.
2. Remove the cap from the mouthpiece and shake the inhaler vigorously.
3. If you haven’t used the inhaler for a week or more, or it is the first time you have used the inhaler, spray it into the air first to check that it works.
4. Take a few deep breaths and then breathe out gently. Immediately place the mouthpiece in your mouth and put your teeth around it (not in front of it and do not bite it), and seal your lips around the mouthpiece, holding it between your lips.
5. Start to breathe in slowly and deeply through the mouthpiece. As you breathe in, simultaneously press down on the inhaler canister to release the medicine. One press releases one puff of medicine.
6. Continue to breathe in deeply to ensure the medicine gets into your lungs.
7. Hold your breath for 10 seconds or as long as you comfortably can, before breathing out slowly.
8. If you need to take another puff, wait for 30 seconds, shake your inhaler again then repeat steps 4 to 7.
9. Replace the cap on the mouthpiece.

Instructional Video

Other useful advice

• MDIs are much more effective and easy to use when used with a spacer device.
• Practice using your inhaler in front of the mirror a few times. If you see mist coming from the top of the inhaler, or from the sides of your mouth, or your nostrils, you are not inhaling the dose correctly.
• You can check your inhaler technique with your doctor, practice nurse or pharmacist.
• If you can’t get to grips with the coordination of an MDI, there are several other types of inhaler on the market (eg Autohalers, Accuhalers, Diskhalers). You may find some of these easier to use, so talk to your doctor, practice nurse or pharmacist for advice about which one may be best for you.
• If you have weak hands you may find it easier to hold the inhaler with both hands and push the canister down with both index fingers rather than one. There is also a device available called a Haleraid, to help people use aerosol inhalers. Ask your pharmacist or practice nurse about this.
• The propellants used in aerosol inhalers have been gradually replaced by more environmentally friendly CFC-free propellants. The new inhalers may look, feel and taste different but they will supply exactly the same medicine and are just as effective.
• It is important to clean your inhaler regularly about once a week, otherwise it may not work properly. Remove the metal canister and mouthpiece cap from the case of the inhaler. Wash the case and cap in warm soapy water. Rinse in warm water then leave to dry. The holes in the valve sticking out of the bottom of the canister can sometimes become blocked – they can be cleaned with a pin.
• Avoid spraying the inhaler into your eyes, as this can be harmful.
• Always use your medicines as advised by your doctor or pharmacist.
• Don’t give your medicines to anyone else to use, even if they have the same symptoms as you. They may be harmful to other people.
• Always keep medicines out of the reach of children.
• If you forget to take a dose of your inhaler, take the dose as soon as you remember, and then go on as before.
• STORAGE: all inhaler devices should be stored in a cool, dry place and out of direct sunlight.
• Inform your doctor or pharmacist if you accidentally take more than you were supposed to.

Preventers and Relievers

• Inhalers are usually colour coded. Blue inhalers are ‘relievers’. They contain medicine to relax the airways such as salbutamol (eg Ventolin) or terbutaline (eg Bricanyl), and are used to relieve shortness of breath and wheezing. They should work within a few minutes.
• If you find your reliever becomes less effective or you need to use it more frequently, talk to your doctor or practice nurse as soon as possible. Your treatment may need to be altered.
• Brown/beige/white/red/orange inhalers are ‘preventers’ (although some genericsalbutamol inhalers are also white). Preventers contain medicine that reduces inflammation in the airways and prevents asthma attacks. They must be used regularly as directed by your doctor in order to prevent shortness of breath and wheezing.
• If you have a preventer inhaler that contains a corticosteroid (eg beclometasone, fluticasone) you should rinse your mouth with water after using it. This helps prevent the oral thrush that can be a side effect of this type of inhaler.
• If you are using both preventer and reliever inhalers, it is important that you use the reliever first. This helps open the airway passages and allows the preventer medicine to get down into the lungs more effectively.

Spacer Devices

Many people using metered dose inhalers (MDIs) find them hard to use. This is because it can be difficult to coordinate breathing in and pressing the inhaler at the same time. A spacer is a device designed to make an MDI easier to use, thus delivering more medicine directly into the lungs where it is needed. This makes the medicine more effective and reduces the side effects that may occur from inhaling the medicine into the mouth or throat.

A spacer device is a large plastic container, usually in two halves that click together. At one end is a mouthpiece and at the other end is a hole for inserting the mouthpiece of an MDI.

The dose from your inhaler is sprayed into the spacer, from where it can be inhaled without needing to coordinate breathing and pushing down the inhaler canister. It is particularly useful for babies and small children who do not have this coordination. Paediatric spacers have a small mask that fits onto the mouthpiece of the spacer and is placed over the child’s nose and mouth.

There are several brands of spacer device available and they are all different (including Volumatic, Optichamber and Aerochamber). Each spacer device fits different inhalers and so it is important to get the right spacer device that fits your inhaler. The inhaler mouthpiece must fit snugly into the spacer hole. Spacers are available on prescription.

The National Institute for Health and Clinical Excellence (NICE) recommends that spacer devices are used for children with chronic asthma. For children aged under five years they recommend that a spacer (with a facemask if necessary) is used with a metered dose inhaler for administering both inhaled bronchodilators and corticosteroids. For children aged 5 to 15 years they recommend that inhaled corticosteroids are administered in this way.

How to Use Adult Spacers

1. Sit up straight, or stand up, and lift the chin to open the airways.
2. Remove the cap from the mouthpiece of the inhaler and shake the inhaler vigorously.
3. If you haven’t used the inhaler for a week or more, or it is the first time you have used the inhaler, spray it into the air before using it to check that it works.
4. Insert the inhaler mouthpiece into the hole in the end of the spacer (the inhaler should fit snugly and without difficulty – see below).
5. Take some deep breaths and then put your teeth around the spacer mouthpiece (not in front of it and do not bite it), and seal your lips around the spacer mouthpiece, holding it between your lips.
6. Press down on the canister in the inhaler to spray one puff of medicine into the spacer.
7. Breathe in slowly and deeply, then hold your breath for 10 seconds or as long as is comfortably possible.
8. Breathe out, then breathe in deeply again through the mouthpiece of the spacer and hold your breath. It is best to take two deep-held breaths from the spacer for each puff from your inhaler. However, if you find it difficult to take deep breaths, breathing in and out of the mouthpiece several times is just as good.
9. If you need another dose, wait 30 seconds, shake your inhaler again then repeat steps 4 to 8.
10. Don’t spray more than one puff at a time into the spacer. This makes the droplets in the mist stick together and to the sides of the spacer, so you actually breathe in a smaller dose.

How to Use Paediatric Spacers

1. Remove the cap from the mouthpiece of the inhaler and shake the inhaler vigorously.
2. If the inhaler has not been used for a week or more, or it is the first time the child has used the inhaler, spray it into the air before it is used to check that it is working.
3. Attach the mask to the mouthpiece of the spacer.
4. Insert the inhaler mouthpiece into the hole in the end of the spacer (the inhaler should fit snugly and without difficulty – see below).
5. Place the mask over the child’s nose and mouth so that it makes a seal with the face.
6. Press down on the inhaler canister to spray one puff of medicine into the spacer.
7. Hold the mask in place and allow the child to breathe in and out slowly for five breaths.
8. If you need to give another dose, wait 30 seconds, shake the inhaler again then repeat steps 4 to 7.
9. Don’t spray more than one puff at a time into the spacer. This makes the droplets in the mist stick together and to the sides of the spacer, so the child actually breathes in a smaller dose.
10. Using a mask and spacer with a baby can sometimes be tricky. Reassure the baby by cradling them in your arms or on your knee. Gently stroke the baby’s face with the mask so that they get used to it. Talk to the baby and smile – the baby will sense if you are anxious. You can hold the mask over the baby’s nose and mouth to give them a dose while they are sleeping, and babies will also breathe in the medicine while they are crying.

Other Useful Advice

• Your spacer should be cleaned once a month in warm soapy water to prevent build up of medicine residue on the inside. It should be left to drip dry rather than dried with a cloth. Drying with a cloth, or cleaning the spacer more frequently than every month, can cause static to build up on the inside of the spacer, which can impair its performance.
• Spacers should be replaced every 6 to 12 months.
• You can check your inhaler technique with your doctor, practice nurse or pharmacist.
• If you have difficulty pressing the inhaler canister down, you can get a device called a Haleraid, which makes the inhaler easier to use.
• If you can’t get to grips with an MDI and spacer, there are several other types of inhaler devices on the market (eg Autohalers, Accuhalers, Diskhalers). You may find some of these easier to use, so talk to your doctor, practice nurse or pharmacist about what is most suitable for you or your child.
• Always read the printed label and use your medicines as directed by your doctor or pharmacist.
• If you forget to take a dose of your inhaler, take the dose as soon as you remember, and then go on as before.
• Inform your doctor or pharmacist if you accidentally take more than you were supposed to.
• Don’t give your medicines to anyone else to use, even if they have the same symptoms as you. They may be harmful to other people.
• Always keep medicines out of the reach of children.