This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.N.S, Subject name: Pharmacology
Which of the following serum concentration of lithium indicates lithium toxicity? 
Select and explain. 
A. 2 m Eq/L, B. 4m Eq/L, C. 6 m Eq/L, D. 8 m Eq/L
A: 2 m Eq/L
Answer: A: 2 m Eq/L 
Explanation: Ans. (A) 2 mEq/L(Ref: KDT 8/e p476; Katzung 12th/517)Important serum levels of lithiumFor bipolar disorder0.5-0.8 mEq/LFor acute mania0.8-1.2 mEq/LLithium toxicity> 2 mEq /LDialysis done if level> 4 m Eq/L