| The number of doses that will be accurately delivered from the canister is listed on the label. This number should be divided by the average number of puffs used per day to determine when the MDI is empty and should be discarded. | |
| One week prior to this date a note should be made on the calendar to refill the medication. | |
| Unless a dose counter mechanism is connected to the delivery system such as Serevent Diskus, it is not possible to determine when the MDI is empty by shaking alone. This is because the canister is filled with extra propellant which will continue to spray for a period of time even through the medication is has been used up. |
