The Canada Revenue Agency (CRA) document “RC4065 Medical Expenses - 2021” website says that you can claim travel expenses if you had to travel for medical services. There is no mention of prescriptions in the travel section.
You can always double-check with the CRA or ask if an exception be made in your case. If you are in Canada or the United States, you can call the Canada Revenue Agency (CRA) at 1-800-959-8281. If you are elsewhere, you can call 613-940-8495. This page has more ways to contact the CRA: Contact the Canada Revenue Agency
