I have a lot of experience with combining amphetamines (especially meth) with booze.
Theoretically the combination is very dangerous, as both substances increase blood pressure and do all kinds of unhealthy shit with cardio. And both dehydrate heavily. As with everything though it depends on exact dosages of both.
You had 0.5g of cut-to-shit amp with unknown amount of alcohol. Unless you drank a whole bottle of vodka at once, I don't think there's much to worry about, except increased body load and sweating. And increased euphoria and talkativness, which is the reason I combined these 2 on a regular basis and enjoyed it!
I used to go through 2.0+g of good quality meth (maybe 60% pure?), or 2g 4-FA (hopefully 99% pure), and 2-3 bottles of 40% liquor plus 1-10 beers in a weekend festival (overall high time of about 36 hours). The euphoria was amazing, but I could obviously tell it's pushing body quite far.
Still my subjective feel is that amps+booze is safer cardio-wise than coke+booze. Still doesn't mean it's safe, I'm sure the chance for nasty heart conditions or heart attack skyrockets but again, not as much as with coke.
Just drink LOTS of fresh water, just water no syrup, no fanta no cola or other crap, this will make you pee like a dog, you won't lose water where it's necessary in your body which is important.
Another risk though, amps generally overpower booze masking it's negative effects which means you can more easily have alcohol poisoning. The amp makes you feel like you can drink all the liquor in the world but in fact you need less of it to poison yourself because liver are working extra hard.
Now the most important bit: I honestly believe that if amps are combined rarely with alcohol, like once per 3 months, it's not that dangerous combo. BUT if you continue to mix them every time you will develop polydrug addiction, with 1 substance triggering the need to immediately have the other one.
I can no longer sniff meth or 4-FA without craving at least some alcohol or vice versa, only way to overcome dual high addiction is to cease all drugs in the combo...