DPIs deliver asthma medicine as very fine particles of powder. There are many types of DPIs available on the market in the United States. Additional DPIs are sold abroad. Each type of DPI is manufactured by a different pharmaceutical company, and each type of DPI consequently has its specific set of instructions for optimal use.
When your physician prescribes a DPI for treatment of your asthma, have him or her demonstrate the correct way for you to use the DPI and provide you with any avail-able instructional materials. When you fill the prescription, make sure that the dispensing pharmacist includes the directions provided by the manufacturer.
Some pharmacists can advise you on proper DPI usage techniques. Finally, instructions and video demonstrations are available on the Internet on both pharmaceutical and medical Web sites. You can easily access a manufacturer’s Web site by typing your medicine’s name into a search engine’s search box.
Web sites not maintained by pharmaceutical companies are other resources you may wish to consult to learn more about your specific inhaled medicine. The Mayo Clinic’s Web site is an example of a medical site that includes links to videos showing how to use a disk inhaler (like the Diskus) as well as a tube inhaler (like the Flexhaler or Twisthaler).
Even though each DPI comes with its own set of instructions, all DPIs share similar conceptual and design features. They are prized for their ease of use, reliability, efficiency, and convenience. All DPIs are breath activated. When you inhale through a DPI, a precisely premeasured dose of medicine is automatically released. The way you breathe the medicine in (your inhaler technique) allows the drug to travel into your airways where it is needed. The general principle is that you should inhale the medicine via the DPI mouthpiece starting with empty lungs and then hold your breath before exhaling and breathing normally. The basic technique consists of an initial exhalation to empty your lungs, followed by a steady, fairly rapid inhalation from the mouthpiece, and breath holding.
To use a DPI correctly, you first prepare the premeasured dose of medicine, either by rotating and clicking the base of a tube shaped device, advancing a small lever on a disk-shaped inhaler, or by physically inserting powder-containing capsules into a specially designed groove in the device, depending on which type of DPI you have been prescribed. When the medicine is ready, you take in a big breath of room air and then fully exhale it into the room. Once your lungs are complete-ly empty, place your lips around the DPI’s mouthpiece and steadily take a full, deep breath, inhaling the medicine until you cannot breathe in any further. You should not “taste” or “feel” the inhaled medicine.
Once you reach the point when your lungs are full of medicine, hold your breath. You should attempt to hold your breath for up to 10 seconds before exhaling. Count to 10 in your head. After you reach a count of 10, remove the DPI mouthpiece from your lips, and let your breath out. Remember to exhale into the room. Do not exhale into a DPI device.
The reason you need to hold your breath after taking the inhaled dose of medicine is to allow the medicine to deposit in the air passages. When you hold your breath, there is no movement of air in the lungs. Since there is no flow of air, either in or out, your asthma medicine remains in the lungs long enough to be of benefit to you.
Become familiar with the specific DPI device you have been prescribed. Read the manufacturer’s instructions for patient use insert provided with the product. Ask your treating physician any questions you may have. I often ask my patients to bring their DPI with them to their appointment so that they can demonstrate how they use it. I am then able to assess the effectiveness of their technique and, if appropriate, make specific suggestions for improvement.
Note that each DPI not only looks unique, but also has specific characteristics. For example, the disposable Diskus device is packaged in a foil pouch, and its manufacturer states that a Diskus should be used or discarded within 1 month of opening the foil pouch to prevent the medicine from drying out. A Twisthaler must be discarded 45 days after opening or when the counter reads a zero, whichever occurs first. The Diskus and the Twisthaler also have incorporated dosage counters that indicate how many doses of medicine remain in the device.
When the 0 is displayed, your DPI is empty. You should always keep a DPI inhaler in horizontal position when you place your lips around the mouthpiece to inhale medicine. If you are left-handed, you may find it more comfortable and natural to turn the Diskus device over and use it with the label facing down, so that the lever is easier to click into position with your left thumb while holding the device in your left hand. The Diskus should be closed to cover the mouthpiece after each use and does not require any other maintenance or cleaning.
To avoid introducing moisture into a DPI, never exhale into the device. The Flexhaler is similar to the Diskus in that it comes preloaded with medicine. It is shaped like a tube. In order for you to prepare your dose of medicine, the Flexhaler requires you to twist the brown grip at the base of the device fully in one direction as far as it will go and then twist it fully back again in the other direction before you place the mouthpiece between your lips and inhale after a deep exhalation as described above.
It does not matter which way you turn first, clockwise or counterclockwise. You will hear a confirmatory click as you twist. The Flexhaler needs to be primed before you first use it; and as is the case with all DPIs, you should never exhale into the device mouthpiece, which will introduce moisture into the device. The Flexhaler has a dose counter window below the mouthpiece.
It does not actually display the exact amount of doses remaining in the device, but will let you know approximately how many doses are left. As you use the Flexhaler, the numbers will count down by 10. The Flexhaler will count down to 0, which will appear in the center of the window when the Flexhaler is empty. Plan to get a new Flexhaler before you see the 0 in the window. Always recap the Flexhaler after using it to keep it clean and dry; you can wipe the mouthpiece with a dry cloth, but do not wash the device.
Another tube-shaped DPI is the Twisthaler. It has a pink colored base (in contrast to the brown Flexhaler’s base) and has a dose counter that counts down how many doses remain in the device. As the case for the Flexhaler, you will need to prepare the dose by holding the Twisthaler upright and twisting the white cap counterclockwise, which puts the medicine in the device.
Once the medicine is good to go, you can empty your lungs of air and inhale your medicine, as described earlier in this section. The Aerolizer and Handihaler devices require that you load capsules that contain medicine into the DPI before use, and they accept only one dose at a time.