I've never been questioned about bringing any prescription drug across the border here. Suggest you have a look at the
Customs website . Slightly frustratingly there is a great leaflet that you get when you book tickets out of the country to remind you of what you can and cant bring back into the country and can't lay my hands on a copy at this moment.
They are likely to be more concerned with biosecurity aspects of your luggage then personal medication.
Edit:
Medsafe have the
importation rules you are looking for