I’m looking forward to them being more widely available, as available as those stupid, dangerous energy drinks one can get at a gas station convenience store.
Tonic water is the most available. They usually contain a lot of sugar to cut the bitterness.
FDA limits quinine to 83mg/L in tonic waters.
Although not a therapeutic dose, if you take it with a normal zinc supplement you will be accomplishing some prophylactic benefits with safety.