Avrusa Serethi at Serethi Farm has a "buy Adrenaline Rush (35)" topic and when I choose it she seems to give my char something but nothing happens (i.e. I don't get any Adrenaline Rush and she doesn't get any money). When checking UESP it doesn't mention any Adrenaline Rush potion at all that I can see. Anyone who knows more about this?

You using any mods? That doesn't sound like any vanilla issue I've ever heard of.