Like any question about drug interactions, it's best to ask your psychiatrist or pharmacist. I will say that when I first started Lithium ER my psychiatrist (in the hospital) said to avoid caffeine. At the time I was also supposed to stop drinking alcohol completely. I sort of boo-hooed that stopping both alcohol and coffee was like a punishment. I HAD to quit the alcohol (for more reasons other than just mood interference), but I wanted the coffee. He said that I could have one cup in the morning. I was satisfied, because that is pretty much all I drank anyway.

I imagine people out there do drink more than one caffeinated beverage on Lithium. I think I did occasionally have two or three in the form of coffee, espresso, and iced tea, but it would have been better if I hadn't. Definitely if you're a Jolt drinker, it might be good to stop that habit immediately. Even people without a mental illness would probably benefit by stopping a full coffee pot habit or a six-pack of Diet Coke habit.

Like TheSadGirl said, water consumption is important. Actually, many Lithium users get so extremely thirsty they drink a lot of water throughout the day. And pee a lot, too. That's good for the kidneys. Do take care of your kidneys.