The government mostly doesn't pay for drugs in Canada. Each province has its own insurer, and the biggest ones don't cover pharmaceuticals in the general case.

OHIP (the government-run insurer in Ontario, to which taxpayers pay the Ontario Health Premium directly) will sometimes pay some or all the cost of some pharmaceuticals in some cases (i.e, antibiotic-corticosteroid ear drops if you are under 25 or over 65, and have been experiencing an ear infection for longer than 30 days) for some classes of people (mostly youth and seniors); but by no means is there a single buyer in Canada, and there isn't one per province either.

I have bought more pharmaceuticals out of pocket in Canada than I have ever been provided during a covered clinic or emergency department visit, and I technically qualify for the youth drug coverage.

The listings for which drugs are covered under what circumstances can be found here: https://www.ontario.ca/page/check-medication-coverage/

> The reason drugs are cheaper in Canada and Europe is because of the massive negotiating power of a single buyer

Very few countries have single purchasers for pharmaceuticals.

No, but the pharmacies hold only a little bit of power over that stuff. If the single payer health plan won't cover x medicine because y is cheaper and just as effective, x is rarely going to be ordered. X being an equal price to y means x might be some doctor's first line treatment.

> No, but the pharmacies hold only a little bit of power over that stuff.

We're not talking about pharmacies; they don't enter the picture here at all.

> If the single payer health plan

Again, almost no country uses a single-payer health plan for pharmaceuticals, so this is isn't relevant.

I'm sure it's not exclusive