tl;dr: a bunch of vodka redbulls are probably really bad for you, but Red Bull has been controlling the publishing so it’s hard to say for sure. But the bad cases they cite are someone who got trashed and went swimming, someone who binged all day, and a 14-year-old girl. It doesn’t sound like one or two vodka redbulls are going to be significantly worse than just a regular night of drinking. No one drinks red bull or vodka thinking it has no health impact to start with.

I can’t drink them anymore (especially Red Bull) it sends me right in heart arrhythmia and in the hospital. Long time drinker of them and one day it was like throwing a switch.

I don’t miss them or the arrhythmia.

Isn’t harmful may mean if you are reasonably healthy you won’t drop dead on the spot after the first glug.