The ozone layer and metered dose inhalers.

The stratospheric ozone layer plays a crucial role in protecting living organisms against ultraviolet radiation. Chlorofluorocarbons (CFC) contained in metered-dose inhalers (MDIs) contribute to ozone depletion and in accordance with the Montreal Protocol on Substances That Deplete the Ozone Layer established 10 years ago, phase-out strageies have been developed worldwide for this category of agents. Alternatives to CFC-containing inhalers have been developed, such as powder inhalers and those using hydrofluoroalkanes (HFAs) as propellants, which have been shown to be as safe and effective as CFC-containing inhalers and even offer interesting advantages over older inhalers. The transition to non-CFC MDIs requires a major effort to make the new products available and to ensure adequate comparision with the previous ones. It also requires a harmonization of actions taken by industry, government, licencing bodies and patients or health professional associations to ensure adequate information and education to the public and respiratory care providers.