Leading articles How to choose delivery devices for asthma

The inhalation route has many advantages in the treatment of diseases of the respiratory tract. Medication may be delivered directly to its site of action, giving a faster onset and allowing smaller doses of drug to be administered. Systemic absorption of the drug is diminished, reducing systemic side eVects. The drug treatment regimen for the vast majority of patients with asthma is straightforward and is documented in recent guidelines. The choice of which drug delivery device to use is less clear. Rather than being spoilt for choice, we are more frequently confused by the ever increasing number of devices available. What guidance may be given to the paediatrician selecting an inhalation drug delivery device for a patient? The choice depends on the device, the patient, and the drug. Our current practice is outlined in table 1. Spacer devices, used with facemasks for children unable to breathe reliably through a mouthpiece, are the first choice of device for children younger than 5 years. Nebulised delivery of bronchodilator and prophylactic medications is ineYcient and expensive, and nebulisers should be reserved for those unable or unwilling to use metered dose inhalers and spacers. The use of metered dose inhalers alone, breath actuated devices, and dry powder inhalers should be discouraged in this age group. It is important to read studies pertaining to this age group with care, as conclusions of a device’s suitability may be generated across a wide age range, despite inclusion of a small number of subjects younger than 5 years chosen for their ability to undertake advanced respiratory manoeuvres. For children older than 5 years, bronchodilators may be given via a breath actuated metered dose inhaler or a dry powder inhaler. We recommend a spacer device for the administration of inhaled steroids at any age. These are normally given twice a day, for instance on waking and retiring, so arguments that the spacer is not portable are not relevant. However, for low dose steroids, if the child is unwilling to use a spacer, breath actuated or dry powder devices may be chosen in preference to the metered dose inhaler alone. There is no evidence that changing to these devices improves compliance. Drug delivery device There are three main types of inhalation drug delivery device, grouped by the drug dispersion method that they use: pressurised metered dose inhalers, containing a mixture of propellant and drug under pressure; dry powder inhalers, utilising the patient’s inspiratory eVort to disperse medication; and nebulisers, using compressed gas or the vibration of a piezo electric crystal to aerosolise liquids. Adjuncts—such as spacers or holding chambers—may also be used to improve inhalation treatment.