Lithium. My psych NP at the time put me on a ridiculously high dose for my weight, 1800 mg, and I ended up in the ICU for a week with lithium toxicity (had a lithium level of 4.3) kidney failure, and seizures. I'm not saying Lithium is bad, but I will never touch it again, it was just a horrific experience though I know it's very helpful to some people