Your adrenaline device expires at the end of the month shown on the device.
You should allow enough time to make an appointment to see your doctor/nurse practitioner for a new prescription to take to your pharmacy.
Remember that the pharmacy may not have the adrenaline device in stock and may need to order it. In metropolitan areas, it may take a couple of days for the adrenaline device to arrive in the pharmacy. In rural, remote, and regional areas, it is likely to take longer.
It is best to start the process of getting a new prescription at the beginning of the month your adrenaline device is due to expire in case there are any delays.