Replacement for coca cola?

My go to drink is Vodka and Coke. I’ve noticed recently that by the end of the night I have a weird tightness in my chest and it’s ONLY if I’m drinking Vodka & Coke, so I’m putting it down to the cola.

I was just wondering if anyone has any recommendations for moving away from the Cola when I’m on the Vodka, I like most drinks but not really sure what to replace it with!