On March 22, 2017, the Québec government announced that, in order to ensure consistency with the GST/HST treatment which was recently amended by the 2017 Federal Budget, naloxone, including its salts, will be added to the list of non-prescription drugs which are zero-rated, effective March 22, 2017.
Finances Québec Information Bulletin 2017-5, which announces this change, is available via the following link:
http://www.finances.gouv.qc.ca/documents/bulletins/en/BULEN_2017-5-a-b.pdf