A bronchodilator inhaler — or metered dose inhaler (MDI) — is a device used by individuals with obstructive or constrictive respiratory diseases such as chronic obstructive pulmonary disease (COPD) or more commonly, asthma. These inhalers hold medications known as bronchodilators because they relax, or dilate, the smooth muscle lining of the lungs and bronchial tubes. The inner lining of the lungs is made up of small air pockets, or alveoli, that somewhat resemble cauliflower florets in shape. It is within these small structures that oxygen is transferred to the bloodstream to oxygenate body tissues and carbon dioxide is exchanged for exhalation. Administering a dose of bronchodilator medication decreases the effort necessary to inhale, increases the surface area of each alveolus and increases oxygenation by relaxing the smooth muscle lining the respiratory passages.
Both a plastic holder and a small canister of medication make up a bronchodilator inhaler. Some holders are made to be used with multiple medication canisters while others are fused to the medication holder and both items are disposed when the drug is depleted. One end of the "L-shaped" inhaler is molded to fit between a patient's lips while the other arm holds the medication canister. A given or "measured" dose of the bronchodilator is dispensed when the canister is compressed and is to be inhaled orally into the lungs. Depending upon the medication, a prescription may call for one or two "puffs" after the inhaler is shaken to mix the medication solution.
A bronchodilator inhaler can contain short-acting bronchodilating medication or long-acting bronchodilating medication. Many patients with asthma utilize both types to control bronchial spasms. A short-acting bronchodilator inhaler is often used "as needed," or on an emergency basis and should be carried by the patient within reach at all times. Conversely, a long-acting bronchodilator inhaler is usually prescribed to be taken on a regular schedule, such as once or twice per day. While long-acting medications control most symptoms of the respiratory condition, short-acting medications can be used to treat exacerbations caused by exertion or exposure to allergens.
Side effects of a bronchodilator inhaler depend upon the medication held within the inhaler's canister. Most of these medications, however, are known to be distasteful and patients are often advised to rinse their mouths thoroughly after use. Sulfites are also a common ingredient within the medication mix and these compounds are known to cause allergic reactions in some patients. General side effects of bronchodilator inhaler use include dizziness, a rapid heart rate or increased blood pressure.