A non-spraying metered-dose inhaler (MDI) is often caused by a simple mechanical failure that can be quickly resolved with basic troubleshooting. The MDI uses a pressurized canister to deliver a precise dose of medication through a plastic actuator. When the delivery mechanism fails, the problem is typically due to a lack of supply, improper assembly, or a physical blockage from medication residue.
Initial Checks for Assembly and Supply Issues
The fastest way to check the device is to confirm the medicine supply and structural integrity. Check the dose counter immediately; if it displays zero or enters the red zone, the canister is empty. The counter is the definitive guide, as a heavy canister may only contain residual propellant, not active medication. Also, check the expiration date printed on the canister, as expired medication should be replaced regardless of the dose count. Finally, ensure the metal canister is securely inserted into the plastic actuator, and visually inspect the mouthpiece for any protective cap or foreign object obstructing the spray hole.
Step-by-Step Guide to Clearing Blockages
The most frequent cause of a non-spraying MDI is medication residue clogging the tiny nozzle within the plastic actuator. To correct this, first remove the metal canister from the plastic actuator, as the canister must never be exposed to water. Wash the plastic actuator under warm, running tap water for 30 seconds, ensuring water flows through both the top (where the canister sits) and the mouthpiece end. This dissolves the sticky medication particles that have hardened and blocked the spray aperture.
Avoid using a pin, needle, or any sharp object to manually clear the blockage, as this can permanently distort the nozzle’s precise geometry. After rinsing, shake the actuator vigorously to remove excess water, then place it on a clean surface to air-dry completely. Allowing the plastic piece to dry thoroughly, ideally overnight, is important because residual water can mix with medication and contribute to future clogging. Reassemble the inhaler only after the plastic actuator is completely dry.
Re-Priming the Inhaler Mechanism
After cleaning the actuator or if the inhaler has been unused for an extended period, re-priming is necessary. Priming reactivates the propellant system and mixes medication that may have settled while the device was inactive. This process ensures the initial spray contains a full, accurate therapeutic dose, not just propellant.
To prime the device, shake the assembled inhaler well for five seconds to evenly distribute the medication. Point the mouthpiece away from your face and press down firmly on the canister to release a test spray into the air. Repeat this process, typically releasing two to four test sprays in total, shaking the device between each actuation. Re-priming is required if the inhaler has not been used for several days or weeks.
Recognizing When the Device Cannot Be Repaired
Troubleshooting steps will not always fix a non-spraying device, and knowing when to replace the inhaler is important for safety. If the dose counter reads zero, the inhaler must be discarded because the remaining contents are mostly propellant without therapeutic medication. Physical damage, such as visible cracks in the plastic actuator or a bent metal canister, signifies that the internal mechanics are compromised and the device should not be used.
If cleaning and re-priming fail to produce a consistent, fine mist, replacement is necessary. Never attempt to dismantle the metal canister itself, as this is dangerous due to the pressurized contents. If the medication is needed urgently and troubleshooting fails, contact a pharmacist or healthcare provider immediately for guidance on obtaining a replacement dose.