New inhalation devices.

ll is now accepted that inhaled bronchodilator therapy is, whenever possible, to be preferred to oral treatment in the routine management of reversible airflow obstruction [1). However, during the last two decades we have repeatedly been reminded that many patients have great difficulty in using the conventional pressurized metered dose inhaler (MDI) [2-6], today's most frequently prescribed inhalation device. Inefficient use leads to decreased therapeutic efficacy [7], and it is possible, therefore, that at least half of our adult patients, and perhaps a greater proportion of children, are getting little or no benefit from using inhalers because of poor inhalation technique [6, 8, 9]. It appears that the magnitude of this problem has been appreciated, and recently new devices have been developed which should allow more patients to benefit from inhaled therapy in the future. It is unlikely that the MDI will be completely superseded by non-pressurized inhalers, but I believe that the future of the conventional MDI is limited. In the past this device has been modified in attempts to make it easier to use. The development of spacer systems was of great clinical importance [10], and large-volume spacers will continue to havp a role in the management of asthmatic patients in the; foreseeable future. Smallvolume extension spacer devices are of less value and may be replaced by the new inhalers. Spacer attachments were necessary to overcome the inherent problems of a pressurized inhalation system, which is critically dependent upon the patient's coordination of dose release with inspiration. Prior to the introduction of spacer systems a breathactuated pressurized inhaler "Autohaler" had been introduced into clinical practice [11]. Although this is bulky compared to the MDI, it is much smaller than the combination of an MDI .and a large-volume spacer, however, it has the disadvantage of generating a loud "click" when the valve mechanism is triggered. A generous inspiratory effort is also required to actuate the "Autohaler". For these reasons, and also because it was introduced containing isoprenaline as the bronchodilator, it has failed to secure a major share of the market. The concept of a breath-actuated pressurized aerosol is admirable, since the main problem of coordination of valve actuation and inspiration could be solved. On the other hand, the inability of some patients to continue to breathe in when propellant is released