Most individuals diagnosed with COPD are prescribed medications – the most common delivery device for these medicines is an inhaler. For effective usage, it is imperative to know how inhalers work, and how to properly maintain them.
“Ideally, each time someone uses an inhaler, they have one breath to get it right. If they fail to do it right the first time, the medication doesn’t get into the lungs,” explains Patrick Dunne, RRT, FAARC, President of HealthCare Productions, Inc. “I’ve been a respiratory therapist for a long time working with COPD patients, and I’ve noticed these patients don’t do as well with their inhalers as we would like. It’s problematic for patients to remember how to use them.”
There are two types of inhalers individuals with COPD can use—a pressurized metered dose inhaler (pMDI) and a dry powder inhaler (DPI).
pMDI is a small, metal canister that contains both a pressurized gas propellant and medication. When a patient depresses the canister into the plastic “boot”, the pressurized propellant pushes the medication out and the patient inhales it. Each time the inhaler is depressed is called an “actuation.”
“Most people don’t count how many times they use it (actuations) and they aren’t sure how much medication is left after using it for awhile,” says Dunne. “?ere are about 200 actuations inside each canister, and o?entimes many of those 200 are wasted; for example, when the pMDI needs to be primed before using. If you shake it and can still hear something inside, it doesn’t mean there’s medication left. It might just be propellant.”
To counteract this problem, patients can use a dose counter that some of the newer inhalers have built into the plastic boot. Every time a patient actuates their inhaler, the counter number goes down by one. If there is no dose counter, patients should record when and how o?en they actuate the pMDI. Typically, this is done by starting at 200 and then subtracting the number of actuations each time the pMDI is used.
“The Food and Drug Administration (FDA) is encouraging pharmaceutical companies to integrate and retrofit old pMDIs with dose counters, and the industry is moving in that direction as a whole,” Dunne explains. “Another issue with the metered dose inhaler is that patients can sometimes have a hard time with hand-eye breathing coordination. It might take 3-4 actuations to get the medication into the lungs.”
To correct this problem, it is recommended that patients use a “spacer” or holding chamber that is inserted between the pMDI and their lips.
“Now with a holding chamber, when a person actuates the pMDI, the medication mist goes into that chamber and stays suspended inside for 1-2 seconds until the patient inhales the medication from the chamber. This is an important component to improve drug delivery,” Dunne says.
The second type of inhaler an individual with COPD can use is a dry powder inhaler, or DPI..
These are the newest types of aerosol devices, introduced in the 1990s. Drug companies that make medicine for these types of inhalers put it in a very fine powder form, similar to talcum powder, and enclose it in a capsule. That capsule is placed into the DPI and is punctured when it is time to take a dose of medication. THe advantage to this inhaler is that the patient does not need to coordinate their breathing pattern with the spraying of the aerosol like they do with a pMDI inhaler. Once the capsule is punctured, the powder does not go anywhere. The patient just inhales quickly and deeply from the DPI mouthpiece and draws the medication into the lungs.
“With a DPI a patient can inadvertently exhale into it, and the moisture in their lungs causes the powder to clump. If you’re in high humidity areas, that also causes the powder to clump and the medication can’t get into the patient’s lungs,” Dunne cautions.
“An important concern is that patients with really bad COPD cannot take a deep or quick enough inhalation to get the powdered medication into the lungs. Where a spacer can help with a pMDI, there is no accessory device that can help—with a DPI there is only one way to use it.”
Dunne says that for both pMDI and DPI, patients usually use the inhaler 2-4 times a day depending on the medications prescribed. Remember:
If you have further questions about your inhaler, talk to your doctor.
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