Inhalation therapy for infants.

Delivering aerosolised drugs to infants poses a number of challenges. It is clear that drug delivery is possible via the inhaled route but to date it has been difficult to demonstrate clearly therapeutic benefit from the use of any conventional therapy in the vast majority of infants. This is probably related to the nature of pulmonary disease in this age group. While most aerosol scientists focus on factors such as aerosol size and airways geometry drug delivery, as in all age groups, is most dependent upon patient behaviour. A small amount of drug reaches the lungs of distressed infants. Consideration of patient device interactions is vital if successful drug delivery is to be achieved and this includes consideration of mask design. Doses reaching the lungs are generally very low when considered in terms of the nominal dose but when considered in terms of dose delivered per kilogram body weight drug delivery to the lungs is generally similar to or greater than in adults. Upper airways deposition is relatively greater than in older subjects, in large part because of nasal breathing, and this will affect the 'therapeutic index' of some drugs.