Prescription drugs: a question

This isn’t a regular post, but a question.

I thought Canada had laws against advertising prescription drugs, but I keep getting this drug pushed at me on Twitter, both in French and English:

I looked it up. It’s a drug used to treat multiple sclerosis.

I don’t have MS, and I haven’t had any reason to read up on it. Even when I looked it up, I used a private browsing window on a non‑habitual browser, so’s not to leave tracks. So I don’t know why I would be targeted by a Twitter algorithm.

If anyone knows about the law on this, or anything else relevant, I’d be interested to hear about it.