Novel Dosage Forms

Dry Powder Inhalers

This small device is similar to a metered dose inhaler (MDI), but the drug is in powder form. The patient exhales out a full breath, places the lips around the mouthpiece, then quickly breathes in the powder. Note that the technique is different than for MDIs -- dry powder inhalers do not require the timing and coordination that are necessary with MDIs. There are other important differences, so make sure that you always know the proper technique for the method you are using.

Dry powder inhalers are becoming more common, in part because they do not use the "CFC" propellant found in an MDI. (CFCs damage the ozone and will be phased out of MDIs in the next few years.) Dry powder inhalers are as effective as MDIs -- in fact, some may prove to be slightly more effective.

Naturally, there are several disadvantages. If the patient exhales directly toward the device, the powder can be blown out. Also, much of the powder ends up in the mouth, which can cause unwanted side effects -- this is similar to what happens when a patient puts an MDI directly into their mouth. As with MDIs, it is recommended that you wash your mouth after administering the drug.

(Greene Ink, Inc., 2003)

What is a dry powder inhaler?

A dry powder inhaler (DPI) is similar to a metered dose inhaler. Both are handheld devices that deliver a precisely measured dose of asthma medicine into the lungs. The advantage of using a dry powder inhaler is that it is breath-activated, so you don't have to coordinate activating the inhaler (spraying the medicine) while at the same time inhaling the medication. Instead, you simply breathe in quickly to activate the flow of medication. In this way, the breath-activated discharge of medicine...