Substances that can be inhaled into the body through the lungs usually as an aerosol – a suspension of very small liquid or solid particles in air or other gas usually delivered by devices in which the aerosol is kept under pressure in a small hand-held cylinder and delivered in required doses by a release mechanism.
Asthmatic patients (see ASTHMA) find metered-dose aerosol devices to be of value in controlling their attacks. They provide an effective and convenient way of applying drugs directly to the bronchi, thus reducing the risks of unwanted effects accompanying SYSTEMIC therapy. BRONCHODILATOR aerosols contain either beta-adrenoreceptor agents or ipratropium bromide, which is an ANTICHOLINERGIC drug, or a corticosteroid.
Beta-adrenoceptor agents include SALBUTAMOL (US, albuterol), TERBUTALINE, rimiterol, fenoterol and reproterol. Salmeterol is a longer-acting choice for twice-daily use when added to existing corticosteroid therapy (see CORTICOSTEROIDS).
People who use inhalers must be taught carefully how to do it, and observed to check their technique. It is important that they should realise that if the aerosol no longer gives more than transient relief, they should seek medical help.