In the US, it's legal to advertise drugs directly to patients. There's not a lot of places in the world where it happens, I'm assuming Scandinavia is one of them.
I was once on holiday and with US TV, and saw a few times an ad for performance enhancement for older gentlemen. The ad showed an older couple, who first are not very happy, then much happier with each other, frollicking in the long grass and disappearing off shot etc.
While that was happening, the narrator was reading in an impassioned, but also somewhat undulated voice: "side effects include headaches, blurred vision, hypertension, liver failure, paralysis and death" [I can't quite remember the list, basically it went from minor to death, as most drugs do].
For someone not at all used to serious drugs being advertised on prime-time TV, this was quite a thing to see.
The name isn't supposed to make an actual claim about effectiveness--you can't call it "cancercurazine"--but they often try for something vaguely suggestive: Viagra sounds like it makes you 'vital', Wellbutrin makes you feel well, Zyban keeps you away from nicotine, etc.
I've heard--but can't find a source saying--that this is why varenicline is sold under two different names: someone felt like 'champix' was too suggestive.
* My first attempt at a made up drug name was Xaljenzia (my thought process was they seem to love the letters X, J and Z) but apparently there is a Xaljenz so I ended up with this.
So we sort of have a culture where you only really stick to certain brands if you’ve ever had a bad reaction to a copy product. I’ve got a hay fever for instance, and for the past many years I’ve stuck to the same brand of antihistamines because I once bought a box that made me nauseous and I just went back to what I had previous used. This is anecdotal of course, but it took me almost a decade to learn the name and not just ask for the ones in the green box.
The bigger difference I see here is that in the US, I generally got loose pills in a pill box, and here in Norway, I'm more likely to get a standardized amount of pills in blister packs or manufacturer packaging.
Quite simply, prescription drugs advertise in the US because they are both allowed to do it and the name-brand drugs get more people insisting on the name brand because they advertise, even though it costs the person more (sometimes, a lot more).