Dr Richard Russell explains how healthcare professionals can improve care of their patients with asthma by selecting the most appropriate inhaler for each individual

Asthma is one of the most commonly seen respiratory diseases in primary care.1 This inflammatory disease of the lung affects over 5 million people in the UK,2 with patients ranging from infants to the elderly. Some experience only mild attacks, while others spend many days a year in hospital with a debilitating and critical illness. Asthma is one of the very few medical diseases that can rapidly change from being asymptomatic to life threatening in a matter of minutes. The cost of asthma to the NHS has been estimated to be around £900 million,2 much of which is accounted for by those patients whose condition is not well controlled.3

Cost-effective treatments are now available, which are relatively safe and, in the majority of cases, enable patients to regain some degree of control over their lives and manage their asthma themselves.

Inhaled therapy using corticosteroids and bronchodilators is the mainstay of asthma treatment.4 When taken as prescribed and when used effectively, these treatments reduce asthma attacks, minimise symptoms, and prevent long-term lung damage (remodelling), which occurs with uncontrolled inflammation.5,6

Need for the guideline

In order for a treatment to work it has to be taken by the patient in an effective manner. This may sound easy and many practitioners assume that it is as simple as writing out a prescription; however, that presumption is a mistake. Evidence shows that many patients are still suffering from asthma symptoms unnecessarily and that poor compliance with asthma medication is one of the main reasons for this.7,8 The incorrect use of inhaler devices by patients leads to unintentional non-compliance. When prescribing, GPs need to select the correct device for each individual patient from the many that are available.9 It is with this in mind that the new Consensus guideline on the use of inhaler devices in asthma was conceived and written.10

The British guideline on the management of asthma4 from the British Thoracic Society/Scottish Intercollegiate Guidelines Network is a comprehensive guide to managing this condition. It is strictly evidence based and provides information on how to manage every facet of asthma for all groups of asthma patients.11 Thus it does not stray far away from areas with a very strong evidence base and, therefore, does not make firm recommendations in some areas; which individual inhaler to select is one such area.

National guidance on use of inhaler devices for children is available from NICE12,13 and several specific Cochrane reviews compare inhaler devices.14,15 With the new Consensus guideline on the use of inhaler devices in asthma,10 the guideline development group aimed to provide practical help to prescribers of inhaled asthma medication. The group worked with the available evidence to make recommendations, and where evidence was lacking a pragmatic and experiential approach was taken.



Role of primary care in asthma management

Increasingly, practice nurses are helping with the workload of asthma reviews, and are advising patients on decisions as to which device is best for them to use. These interactions occur both opportunistically and at asthma reviews.

Table 1: QOF Indicators for asthma


Payment stages


The practice can produce a register of patients with asthma, excluding patients with asthma who have been prescribed no asthma-related drugs in the previous 12 months




The percentage of patients aged eight and over diagnosed as having asthma from 1 April 2006 with measures of variability or reversibility


The percentage of patients with asthma between the ages of 14 and 19 years in whom there is a record of smoking status in the previous 15 months




The percentage of patients with asthma who have had an asthma review in the previous 15 months


Total Points

Choosing the correct inhaler device

There are many factors to consider when choosing an inhaler device. Some are patient related, some drug related, and some related to device alone. Some key questions to consider include:

  • which drug should be chosen?
  • which devices deliver the selected drug?
  • can the patient use the device effectively?
  • is the dosing regimen suitable for this particular patient?
  • does the device effectively deposit the compound in the patient’s lungs?
  • does the patient agree with the overall management plan?
  • is the choice cost effective?
  • are local recommendations being complied with?

Choosing the best device for any individual to use is not easy. It is against this background that the consensus guideline development group was formed in the autumn of 2007. Each different class of device was considered in turn. There are advantages and disadvantages to each, which should be taken into consideration for each individual asthma patient. The consensus guideline provides an algorithm (see Figure 1) that will help the healthcare professional to review their selected inhaler device for the patient. Table 2 shows selected features of each inhaler device for asthma.10

Figure 1: Algorithm for selection of the most appropriate inhaler device for each asthma patient

Algorithm for selection of the most appropriate inhaler device for each patient

HCP=healthcare professional; pMDI=pressurised metered-dose inhaler

Table 2: Selected features of each type of inhaler device for asthma10


Device type






Cold freon effect


Required coordination between actuation and breath


Ease of technique/breathing




Small, portable, discreet




Yes (reduced with HFA devices)






pMDI + spacer


Bulky, not easily portable












Small, portable, discreet




Yes (reduced with HFA devices)








Small, portable, discreet










pMDI=pressurised metered-dose inhalers; HFA=hydrofluoroalkane; BAI=breath-actuated pMDIs; DPI=dry powder inhalers

Drug deposition

One uncertainty of inhalers is to what degree they deposit the active compound into the lungs and how much is left in the mouth and pharynx. Deposition needs to be taken into account as side-effects are often caused by oropharyngeal build up.17 Technique, device characteristics, and drug particle size all affect deposition;18 a factor that should be considered when prescribing an inhaled corticosteroid.


Pressurised metered-dose inhalers

The most commonly prescribed device in the UK is the pressurised metered-dose inhaler (pMDI).10 This ubiquitous device has been the mainstay of asthma management in the UK. It is relatively cheap and relies upon a propellant to drive the drug into the lungs in a coordinated effort with inspiration.

Advantages of pMDIs include:10

  • availability for a wide range of medications
  • they are portable and carry multiple doses
  • they are familiar to the UK public.

Disadvantages of pMDIs are:10

  • they are not efficient at drug deposition and are complicated to use
  • the propellant is cold and can lead to a cough reaction in some patients (the cold freon effect)
  • good coordination between activation of the device and taking a breath is essential.

Breath-actuated pMDIs have been developed in order to make coordination less of a problem. These are generally easily taught and simple to use, however they are only available for a limited range of drugs. Again the ability of patients to use them will vary and cannot be taken for granted; technique should be checked at every opportunity, even with the simpler devices. Training in use is essential for all inhalers and particularly so for pMDIs. A patient’s ability to use a pMDI can improve with training.

Pressurised metered-dose inhalers plus spacers

The addition of a spacer device to a pMDI dramatically increases lung deposition and reduces the effect of the cold propellant. Spacers are particularly useful for the young and reduce the need for a coordinated breath. Unfortunately they are also bulky and indiscreet, rendering them unpopular with some patients, and they are not compatible with all pMDIs.10


Dry powder inhalers

The dry powder inhalers (DPIs) use the patients own inspiratory flow to create an aerosol of the medication and small particles are inhaled into the lungs.


Advantages of DPIs include:10


  • they are generally easily taught and simple to use
  • there is no cold freon effect
  • many DPIs have dose counters
  • drug deposition is better with DPIs than with pMDIs.

Disadvantages are:10

  • the patient must be able to trigger them and achieve the target flow rate required to create the aerosol
  • they may be more expensive than pMDIs.

Cost effectiveness

Cost effectiveness is another factor to consider, but direct cost comparisons between devices are difficult to make. Costs vary according to device, dose, and schedule.10 In general, the base cost of a pMDI is less than other devices, however if lung deposition is taken into account, comparisons become more problematic. If lung deposition is also taken into account, comparisons become even more difficult. In practical terms, a cost-effective inhaler must meet the following criteria:

  • the patient must be able to use it effectively
  • the patient must use it regularly
  • the chosen device must control the patient’s asthma effectively and thus prevent the real problem: asthma attacks and admission to hospital.

Devices for special groups of patients

It is important to consider the particular needs of special groups of patients with asthma. They include:10


  • the elderly who may have physical difficulties with setting and triggering some devices
  • children who may have difficulty with breath coordination and achieving high inspiratory flow rates
  • patients with cognitive impairment who may find the use of a complicated multi-step inhaler difficult, and alternatives may need to be found; we often forget to consider the cognitive ability of our patients when teaching them about new devices.

Reviewing your choices

Finding the right inhaler for any individual patient requires time, knowledge of the options (see Figure 1), training in how to use the device, and an ability to teach and check technique. The choices made for a patient will need to be reviewed and their inhaler technique checked on a regular basis at planned asthma reviews. Of course, clinical efficacy will be paramount in subsequent assessments.


The Consensus guideline on the use of inhaler devices in asthma is a welcome addition to the current guidelines and will improve the management of asthma. This area is short of high quality trial evidence and has often been taken for granted. If a patient cannot use a prescribed device, then both the patient and the practitioner will have wasted time, money, and effort. Moreover clinical care may be compromised. If we select the right drug, at the right dose in the best device for each patient then we will be managing asthma more effectively and will see the clinical benefits.

Practice-based commissioning take-home messages

written by Dr David Jenner, NHS Alliance PBC Lead

  • Asthma is a significant cause of expenditure in a PBC budget (in terms of prescribing and hospital costs)
  • Pressurised metered-dose inhalers are the most commonly prescribed inhalers, but they are used incorrectly by approximately 60–90% of patients
  • Choice of inhaler and correct inhaler technique is vital to achieve cost-effective care—trained practice nurses and pharmacists can enable this
  • Practices could consider asking community pharmacists to check inhaler technique in asthma patients—pharmacists receive a fee of about £27 for a medicines-use review
  • The cheapest inhaler does not always save money if it results in poor asthma control
  • Hospital admissions for uncontrolled asthma are expensive: £1136 for an uncomplicated admission; £217 for a first out-patient appointment (2008 tariff)a

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