Amount of drug delivered to the patient can vary greatly

Spacer devices are becoming increasingly popular for the delivery of inhaled drugs in the treatment of asthma. They reduce the problems of poor inhaler technique with metered dose inhalers, largely eliminate oral absorption of inhaled corticosteroids,1 and have been shown to be as effective as nebulisers in the treatment of acute severe asthma. By the attachment of facemasks they can be adapted to treat patients of all ages.2 Their popularity has led to a rapid increase in the number of different types of spacer available.

As with other inhalation devices, such as nebulisers, the proportion of the dose of the drug that the patient actually inhales may vary greatly with different spacers. Despite the apparent simplicity of the designs, spacer choice and method of use may dramatically alter the amount of drug available for inhalation. Recent laboratory studies,3 4 5 6 7 supported by emerging pharmacokinetic evidence and radiolabelled deposition studies,8 9 10 demonstrate where the incorrect use of a spacer can affect the amount of drug delivered.

Multiple actuations of the metered dose inhaler into the spacer before inhalation may reduce the proportion of the drug inhaled.3 4 5 6 Five actuations of …