An inhaler is a device that delivers medication directly to the airways, managing conditions like asthma and COPD. How long an inhaler lasts depends on two limitations: the chemical stability of the medication and the mechanical limit of the device itself. Understanding both the expiration date and the dose count is necessary to ensure the inhaler remains effective when needed.
The Two Lifespans: Expiration Date and Dose Count
Every inhaler has a printed expiration date, which is when the manufacturer guarantees the full chemical potency and stability of the drug. This date is determined through rigorous testing to ensure the active ingredients remain at the intended strength. Once this date passes, the drug’s effectiveness is no longer guaranteed.
The second lifespan is the dose count, referring to the finite number of sprays or “actuations” the inhaler is designed to deliver. Most modern inhalers feature a dose counter that tracks the number of puffs used, ticking down from a set number (e.g., 200 or 120). This mechanical limit indicates when the device has dispensed its full supply of medication. After the counter hits zero, any subsequent spray is often just propellant gas without a therapeutic dose of medicine. The inhaler must be discarded when the expiration date is reached or the dose counter reads zero, whichever occurs first.
Tracking Doses and Planning Refills
The most reliable method for monitoring an inhaler’s remaining life is checking the built-in dose counter, a standard feature on most newer devices. These counters may be digital displays or small windows showing a decreasing number of doses. Some counters use color-coding (e.g., changing from green to yellow) to provide a visual warning that the supply is running low.
For inhalers without a dose counter, users must rely on manual tracking. This involves checking the total puffs listed on the packaging and calculating the lifespan based on daily usage (e.g., 200 doses used four times daily lasts 50 days). Users should initiate a prescription refill well before the dose counter approaches zero, ideally when 20 to 40 doses remain, to avoid a gap in medication availability. Older methods like the “float test,” where a canister is placed in water, should be avoided, as they are inaccurate and may damage the device.
Proper Storage for Maximum Efficacy
The way an inhaler is stored directly influences how long the medication maintains its full strength until the expiration date. Inhalers should be kept at controlled room temperature, typically around 77°F (25°C), with a safe range usually between 59°F and 86°F (15°C to 30°C). Exposure to extreme temperatures can cause the medication or propellant to degrade prematurely, shortening the inhaler’s effective life.
Avoid leaving the inhaler in a vehicle or on a sunny windowsill, where temperatures fluctuate dramatically. Moisture and humidity also pose a threat, especially for dry powder inhalers (DPIs), as water can cause the powdered medication to clump and become ineffective. Store the device away from areas like the bathroom, where steam is common, to preserve the drug’s integrity.
Risks of Using Expired Medication
The primary danger of using an expired inhaler is reduced potency, meaning the active drug may not work as intended during a respiratory event. Medication naturally breaks down over time, and once the expiration date passes, the manufacturer cannot guarantee the drug will deliver the correct dose. Relying on weakened medication can lead to delayed or inadequate treatment during an asthma attack or flare-up, potentially causing a severe medical emergency.
The risk is compounded when a metered-dose inhaler is used past its dose-count limit. While the device may still release a spray, the ratio of drug to propellant becomes inconsistent or nonexistent, resulting in the user inhaling only the inert gas.
Although rare, some medications can chemically change after expiration, but the loss of efficacy remains the most significant health concern. Using an ineffective device increases the risk that an underlying condition is not being managed properly.