It is important to know how long your inhaler medication will last so that you will not unexpectedly run out of medicine. Unfortunately, you cannot see inside the canister like a bottle of pills to know when your medication is going to run out. So how can one figure out how much medicine is left?
The number of puffs in each canister should be printed on the side of the inhaler. You will simply divide the total number of doses in the canister by the total number of doses taken per day. For example, Flovent, a steroid controller medication, has 120 puffs per canister. If your healthcare provider has prescribed 1 puff twice per day, your inhaler will last 60 days (120 divided by 2). Albuterol inhalers, a rescue bronchodilator, on the other hand, has 200 puffs per inhaler. If you use 2 puffs per day, your rescue inhaler would only last 100 days. If you are using your short-acting bronchodilator more than twice per week or if you need to get it refilled more than twice per year, discuss increasing your controller medication with your healthcare provider.
If you keep a separate daily log of how often you are using your controller and rescue inhaler, you will be able to tell after several days how long your inhaler will last. I usually recommend to my patients that they write a “dead” date on their controller inhaler when they pick it up from the pharmacy. The patients simply figure out how long the inhaler will last and write the date it is expected to run out on the inhaler so that they can pick one up from the pharmacy. I also advise patients to always have an extra rescue inhaler on hand.
Institute for Safe Medication Practices. Consumer Information Accessed February 18, 2009. Is Your Asthma Inhaler Running on Empty?