 | Click the icon to see an image of a holding chamber. |
MDI-delivered drugs must be used regularly as prescribed, and the patient carefully trained in their use, for the drugs to be effective and safe. Some patients hold the MDI too close to their mouths, or even inside them. Others may exhale too forcefully before inhalation. The holding chamber, or spacer, allows the patient additional time to inhale the medication, improving delivery. They vary, however, in their ability to deliver medication. Often MDIs continue to deliver propellant after the drug has been used up. Patients should track their medicine and throw the device away when the last dose has been administered.
 | Click the icon to see an illustrated series detailing metered dose inhaler use. |
Breath-Actuated Inhalers. Breath-actuated rotary inhalers (e.g., Easi-Breathe and Autohaler) deliver the drug directly to the back of the throat as the user inhales. Their primary advantage over the MDI is their ease of use. They also do not use CFCs as propellants. In comparison studies, patients have been very successful with the breath-actuated inhalers.
Dry Powder Inhalers. Dry powder inhalers (DPIs) deliver a powdered form of beta2 agonists or corticosteroids directly into the lungs. They also do not use CFCs. Such devices include Rotahaler, Spinhaler, Turbohaler, Clickhaler, Easyhaler, Diskhaler, Discus, Twisthaler, Spiros, and others. DPIs are as effective as the older devices, and generally have a better taste and are easier to manage. They may differ among themselves, however, in their ability to deliver drugs into the airways. In one study, for example, the Turbohaler was easier to use than the Diskhaler, achieving better delivery. The Discus is another effective DPI; it has a dose counter and protects against exhalation effects.
Humidity or extreme temperatures can affect these inhalers' performance, so they should not be stored in humid places (bathroom cabinets) or locations subject to high temperatures (glove compartments during summer months).
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