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There are loads of types of inhalers! You need to be able to tell a patient how to use each type, and what type of drugs can go in each type.
With all inhalers, the amount of drug deposited on the mouth and pharynx is very high. Generally it is about 85% (even with good technique). This can improve to about 75% with different types of inhaler.

How a spacer works

A spacer not only allows for better co-ordination of breathing and dispensing the drug, but it also has a molecular effect. Larger molecules of drug are the ones that normally deposit themselves on the mucosa, and thus these are the ones that can lead to candida, hoarseness of the voice or systemic effects if swallowed. But in a space, the larger molecules remain in the spacer, and only the smaller drug molecules are actually inhaled.

Aerosol MDI

  • Shake the canister
  • Take the cap off – check there is nothing inside; the opening is clear
  • The patient does a normal expiration (not a full expiration)
  • Put the nozzle in your mouth, and at the same time as breathing in, press down on the top
  • Do a full inhalation
  • Hold your breath for 10 seconds
  • Even with a very good technique, only 15% of the drug reaches the lungs – the other 85% is deposited on the wall of the pharynx and ultimately swallowed

Drugs used

  • Salbutamol
  • salmeterol
  • Beclomethasone
  • Lots of others!

With a spacer

These reduce the risk of thrush (candidasis) as well as alleviating the need for synchronised breathing and activation of the inhaler. Newer spacers are smaller, and also make a musical note when you are breathing too hard to tell you to reduce the strength of breaths.
  • Need to be replaced every couple of months
  • Need to be washed every day in soapy warm water, and only let them dry by evaporation (drip drying) – do not wipe it dry! – this causes build up of static electricity
  • They reduce the velocity of the drug particles, and thus reduce the number of particles being deposited on the mouth and pharynx
  • To use the spacer – put one end in your mouth, and activate the drug. Then take 5 normal sized breaths very gently in and out. Do this twice – one for each ‘puff’ of the drug.

Washing the mouth

If you rinse out your mouth with water after using the inhaler this reduces the risk of thrush and irritation to the mucosa of the mouth and pharynx.


  • Often no dose counter
  • Requires co-ordination of breathing and pressing – can be difficult for the very young and very old, or those with arthritis, or other problems with the hands
When to take the ‘releiver’
  • When experiencing SOB / other symtoms
  • Before an event that you know often causes symptoms – e.g. exercise in execise induced asthma
If symptoms are not relieved in the usual manner, then do not hesitate to call an ambulance!

Breath Actuated Inhaler

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This is a breath activated device, and thus had the advantage that breathing and pressing don’t need to be co-ordinated.
  • Shake the device
  • Remove the cap
  • Prime the device – pull the red lever up so that it clicks
  • Whilst sat upright, take a normal breath out.
  • Inhale slowly and deeply – don’t be put off by the click. Keep breathing in to a full inspiration, and then hold your breath for 10 seconds
  • Push the red lever back down. Replace the cap
  • Remember the tell the patient they wont feel the spraying sensation at the back of the throat and that this is normal. They may still be able to taste the drug though.


  • Salbutamol
  • Beclomethasone


  • Patient may not remember to ‘prime’ it before each use
  • Can be difficult for some people to prime; it is possible to press up the red lever using the edge of a table.
  • It makes a loud clicking noise when you inhale, which can be offputting
Breath activated. This time, the device is primed by opening the cap, and not by any sort of lever.
  • Shake it
  • Hold it upright, and open the cap, to prime the device
  • Sit upright, do a normal breath out
  • Seal lips tightly around mouthpiece. Be careful not to block the holes on top with your fingers.
  • Inhale slowly and deeply. Do not stop breathing in when you hear the inhaler puff. At the end of the breath, hold your breath for 10 seconds
  • Close the cap, with the inhaler upright
  • Repeat if you require another dose
Again, the patient will not feel the drug hitting the back of the throat, but they may taste it
Often, this has a dose counter to tell you the number of remaining doses
  • Salbutamol
  • beclomethasone
  • Patients can forget that the cap needs to be closed between doses.
  • Patient has a tendency to put their finger over the top of the device (like with an MDI), and here at the top there are vents to allow air in – so you mustn’t cover them!
  • Some patients like to take the top off and use it like an MDI – tell them not to do this!


This is a dry power inhaler. Although the two inhalers described previously were breath activated, they were not dry powder.


  • Seretide (salmeterol and fluticasone)


  • Has a bit of a complicated method of priming

Quick drug summary

Brand names
β2- agonist
Short acting
MDI, inhalation solution (nebulizer)
β2- agonist
Long acting
Oxis, Atock
β2- agonist
Long acting
MDI, DPI inhalation solution, tablet
Brethine, Bricanyl, Brethaire
β2- agonist
Atrovent, Apovent
Short acting
Inhalation solution
Long acting
Inhalation solution
Becotide, Qvar
Rhinocort, pulmicort
*DPI = dry powder inhaler

Combination inhalers

Seretide – salmeterol + fluticasone – can be MDI, or DPI in the form of Accuhaler (diskus)
Symbicort – formeterol + Budesonide – usually DPI in the form of Turbohaler
For breath activated devices:
  • Can breathe slightly harder – but still need to take a full long breath!This is necessary to separate the particles out, and allows for better absorption
For powered devices:
  • Take a very gentle long deep breath in – the particles are dispersed by the device itself, you don’t want to breathe in too hard, as you will end up with them all sticking to the back of your throat!


  • Murtagh’s General Practice. 6th Ed. (2015) John Murtagh, Jill Rosenblatt
  • Oxford Handbook of General Practice. 3rd Ed. (2010) Simon, C., Everitt, H., van Drop, F.
  • Beers, MH., Porter RS., Jones, TV., Kaplan JL., Berkwits, M. The Merck Manual of Diagnosis and Therapy

Read more about our sources

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Dr Tom Leach

Dr Tom Leach MBChB DCH EMCert(ACEM) FRACGP currently works as a GP and an Emergency Department CMO in Australia. He is also a Clinical Associate Lecturer at the Australian National University, and is studying for a Masters of Sports Medicine at the University of Queensland. After graduating from his medical degree at the University of Manchester in 2011, Tom completed his Foundation Training at Bolton Royal Hospital, before moving to Australia in 2013. He started almostadoctor whilst a third year medical student in 2009. Read full bio

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