METERED-DOSE INHALERS - CURRENT AND FUTURE USES

Respiratory disease poses an enormous burden on individuals and societ y. Asthma and chronic obstructive pulmonary disease (COPD), the diseas es discussed here, contribute towards a substantial proportion of ill health and cost to the NHS and the economy. Most health professionals consider the inhaled route to be the best method of delivering drugs t o the respiratory system. Four types of inhaled delivery system are in use: pressurised metered dose inhalers (pMDIs); dry powder devices; p MDIs and large volume spacers in combination; and nebulisers. In the U K pMDIs are the cheapest type of device on the market and are usually the method of choice for those patients able to use them. Internationa l agreement to phase out CFCs has led to the development of alternativ e propellants for pMDIs. The role of pMDIs is predicted to increase in the future. Demand for pMDIs to treat asthma is likely to increase as the introduction of clinical guidelines extends best practice, and th eir use to treat patients with COPD is increasing. Novel drugs for the respiratory system, including gene therapy and drugs for non-respirat ory disorders, may well employ pMDIs as a delivery system in the futur e.