Asthma drug delivery devices for childrenBMJ 2000; 320 doi: https://doi.org/10.1136/bmj.320.7236.664 (Published 11 March 2000) Cite this as: BMJ 2000;320:664
It may be time to adopt a common strategy to simplify treatment
- Christopher O'Callaghan, senior lecturer in paediatrics1,
- Peter W Barry, consultant paediatric intensivist ()2
- Leicester Royal Infirmary, Leicester LE2 7LX
- Leicester Royal Infirmary Children's Hospital, Leicester LE1 5WW
The drug treatment regimen for most patients with asthma is straightforward and is documented in the British Thoracic Society guidelines.1 The choice of which drug delivery device to use is less clear as we become more confused by an ever increasing choice. For example, when a child with asthma taking prophylactic steroids is seen in clinic or the accident and emergency department for the first time the parents are often unsure which inhalational devices the child uses. If the child is not taking steroids by nebulisation the clinician has a 1 in 125 chance of guessing the correct combination of inhalation device, drug, and strength of inhaler that the child is using. It should be possible to devise a simple prescribing strategy that would avoid this confusion.
The confusion is added to by the way devices are marketed. In several cases insufficient published information is available to allow clinicians to make an informed choice. Promotional material is often based on unpublished data on file or non-peer reviewed abstracts. Many people assume that drug delivery devices are strictly regulated, but this is not so. A device manufacturer can make a new spacer or nebuliser device and place it on the market without providing information on the amount or variability of drug that it is likely to deliver. Devices such as nebulisers may be bought over the counter by parents. Depending on their choice the amount their child may receive may vary by up to four fold.2 The importance of knowing the dose inhaled has been acknowledged in the recent asthma guidelines.1 One study has shown that for the same prescribed, “nominal” dose the Turbohaler dry powder device delivers twice as much drug to the lungs as a conventional metered dose inhaler.3 Similar information on the dose of drug actually delivered from different devices is now required to take away the guesswork and allow recommendations to be made by major bodies.
Despite the plethora of devices, and the need for better information, there is broad agreement on the choice of inhaler to use for particular age groups. This agreement could be used as the foundation of a simple strategy for the use of inhalational devices.
The recent British guidelines on asthma management have supported the wider use of spacer devices.1 Such devices, with or without facemasks, have now displaced nebulisers as the first line of drug delivery to children. Ease of use, decreased systemic absorption of the drug, reduced treatment times, and reduced cost argue strongly in their favour. Dose consistency from them is likely to improve when the dose variability due to static charge is overcome.4 This may be achieved by the use of antistatic materials, such as metal, 5 or by strategies such as washing spacers in a detergent.6 Only when a young child refuses a spacer is a nebuliser appropriate.
The first choice for inhaled steroids in older children, especially for a large dose, is a spacer device. Again the dose a patient receives will depend on the spacer chosen. If compliance with a spacer is likely to be a problem and low doses of inhaled steroid are being used dry power or breath actuated devices are alternatives. The use of a pressurised metered dose inhaler alone is not recommended because of problems with inhaler technique. For the delivery of bronchodilators the choice is between a dry powder inhaler and a breath actuated device. A spacer device may be kept in reserve to administer a larger dose of the bronchodilator for acute exacerbations of asthma.
Consultants on the same ward or general practitioners in the same practice often choose different drug delivery devices for their patients, and, not surprisingly, nurses and junior doctors are often confused about which device and which strength of which inhaler have been prescribed. Nursery staff and school teachers faced with a cupboard full of different inhalers have similar problems. Such confusion among healthcare professionals would be reduced and asthma treatment improved if a limited number of drug delivery devices were used in a region.
For example, most children aged under 5 cannot perform the respiratory gymnastics needed to use a dry powder or metered dose inhaler reliably, and a spacer device (with or without a facemask) is widely agreed to be the first choice for drug delivery to them. A single spacer and a single nebuliser system, for back up use if the child will not tolerate a spacer, could be chosen for use in each region. For older children a specific powder or breath actuated inhaler could be chosen for delivery of bronchodilators. For children on a low dose of inhaled steroid who are not keen to use a spacer, a similar device to that chosen for their bronchodilator may be used. One could envisage such an approach extending to adult patients in the same region. Thus the choice of drug delivery devices might be limited to just three in a whole purchasing authority. This approach may allow us to devote more time to counselling and focusing on compliance.
PWB and CO'C have both received grants and support to attend meetings from the major companies producing inhalational drugs, including 3M Health Care, AstraZeneca, GlaxoWellcome, Rhone Poulenc Rorer, Medicaid, and Pari Medical. PWB's PhD studies were supported by the Astra Foundation. Research staff in the university aerosol laboratory (which is designing inhalational drug delivery devices that may be marketed in the future) are funded in part by grants from AstraZeneca and GlaxoWellcome.