And yes, Guarana is even considered some kind of natural "drug" since it is very strong and its juice can work as some kind of energy drink, just like you said! Even my dad used to buy some guarana energy drinks when we had very long car trips.
"In Serbia and other Eastern European countries, energy drinks based on guarana are marketed under this name (Guarana Antarctica), but without the same sweet flavor as the soda; they have a bitter taste and cardio-accelerating effect."