Do not pay taxes with a prescription
Tax-exempt devices and items when supplied on prescription
If you are a person with a disability, you do not have to pay QST or GST on certain products and services, including the following:
clothing designed specifically for people with disabilities.
source: https://www.revenuquebec.ca/fr/citoyens/taxes/biens-et-services-taxables-detaxes-ou-exoneres/tps-et-tvq/sante/appareils-medicaux-et-appareils-fonctionnels/