Priming an inhaler means shaking it and releasing a few sprays into the air before you inhale a dose. This clears the valve and ensures your first puff delivers the right amount of medication. Without priming, the initial sprays from a metered-dose inhaler can contain less active drug, meaning you get a weaker dose when you need it most. The process takes about 15 seconds, but the exact steps depend on which type of inhaler you use.
Why Priming Matters
Inside a metered-dose inhaler, medication is suspended in a pressurized canister along with a propellant. When an inhaler sits unused, the drug can settle unevenly, and the valve mechanism may not be fully loaded. Priming flushes the system so that each measured puff contains a consistent, full dose of medication.
Research published in the Annals of Allergy tested albuterol inhalers with and without priming and found that unprimed inhalers delivered less drug and produced less therapeutic effect. Once the same inhalers were primed with two waste puffs, the dose output normalized. Skipping this step is a common and easy-to-fix reason people feel like their inhaler “isn’t working.”
How to Prime a Metered-Dose Inhaler
Metered-dose inhalers (MDIs) are the most common type, covering rescue inhalers like albuterol (Ventolin, ProAir) and maintenance inhalers like Symbicort and Advair. The basic process is the same across brands:
- Remove the cap from the mouthpiece.
- Shake the inhaler vigorously for about 10 seconds.
- Point the mouthpiece away from your face and anyone nearby.
- Press down on the canister to release one spray into the air.
- Repeat for the number of sprays your specific inhaler requires.
Most MDIs call for either 2 or 4 priming sprays. Ventolin HFA, for example, requires 4 sprays, shaking well before each one. Symbicort requires 2 sprays. Your inhaler’s packaging will list the exact number, so check the patient insert if you’re unsure.
When You Need to Prime Again
Priming isn’t just a one-time thing. You need to re-prime your inhaler in three situations: when it’s brand new, when it hasn’t been used for a certain number of days, and after you drop it.
The re-priming window varies by brand. Ventolin HFA needs re-priming after 14 days of non-use. Many other MDIs, including Flovent, Advair, and QVAR, typically need re-priming after just 5 days without use. The number of sprays for re-priming is usually the same as the initial prime (often 4 sprays for rescue inhalers, 2 for some maintenance inhalers).
Dropping your inhaler can shift the canister inside the actuator and disrupt the valve. If you drop it, treat it like a fresh inhaler: shake well and prime the full number of sprays before your next dose.
Priming After Cleaning
You should clean the plastic mouthpiece (the actuator) regularly to prevent medication buildup that can clog the spray hole. After washing the actuator with warm water and letting it air dry completely, reinsert the canister, shake the inhaler well, and spray 2 puffs into the air before using it again. This step confirms that the reassembled device is delivering medication properly.
How to Prime a Soft Mist Inhaler
Soft mist inhalers like the Respimat (used for Spiriva, Combivent, and similar medications) work differently from standard MDIs. They use a spring mechanism instead of pressurized propellant, so setup involves more steps the first time around.
To prepare a new Respimat, you first insert the medication cartridge. Press the safety latch, remove the clear base, and push the metal cartridge firmly into the device by pressing it down on a hard, flat surface. Replace the clear base. It helps to write the start date on the side of the inhaler so you can track when to replace it.
To prime, turn the clear base to the right until it clicks, open the cap, and press the dose release button. Repeat this turn-open-press sequence at least three times, or until you see a visible mist coming from the mouthpiece. Once primed, the Respimat does not need to be primed again for regular daily use.
However, if you stop using a Respimat for an extended period, re-priming rules apply. Spiriva Respimat needs one spray if unused for 7 or more days, and a full re-prime (spraying until mist is visible, then 3 additional sprays) if unused for 21 days or more. Combivent Respimat has a shorter window, requiring one re-priming spray after just 3 days of non-use.
Do Dry Powder Inhalers Need Priming?
Dry powder inhalers like the Diskus (Advair Diskus, Wixela) and Ellipta (Breo, Trelegy) do not require priming. These devices use pre-measured doses of dry powder rather than pressurized aerosol, so there is no valve to flush or propellant to clear.
Instead of priming, setup involves loading each dose mechanically. On a Diskus, you open the device by pushing the thumb grip, then slide the dose lever until it clicks. That click means one dose is loaded and ready. Hold the device level during this process so the powder doesn’t spill out before you inhale. The dose counter on the side tells you how many doses remain.
If you accidentally open or click the lever without inhaling, that dose is wasted, but the device itself doesn’t need any additional preparation. Just advance to the next dose.
Tips for Getting It Right
A few practical details make priming more effective. Always shake an MDI before each priming spray, not just once at the beginning. The shaking redistributes the medication evenly through the propellant, so every spray counts. Point the mouthpiece away from your eyes and face, and away from other people or pets. The sprayed medication is active, and you don’t want it landing where it shouldn’t.
If you use your rescue inhaler infrequently, it’s easy to forget whether it needs re-priming. A simple habit: if you can’t remember the last time you used it, prime it. Wasting 2 to 4 puffs is a small cost compared to getting a weak dose during an asthma flare. Some people write the date of last use on a small sticker on the inhaler to take the guesswork out of it.
Keep in mind that priming sprays count against the total number of doses in your inhaler. A Ventolin canister contains 200 puffs, and each prime uses one. If you re-prime frequently, your inhaler will run out sooner than expected, so factor that into refill timing.