Levels of lithium considered toxic?

• A. 0.6-1.2
• B. Over 1.5
• C. 0.8-1.0
• D. 0.2-0.5

Answer: (B)

Lithium has a very narrow therapeutic window, so distinguishing therapeutic levels from toxic ones is crucial. The therapeutic serum range for mood stabilization is about 0.6 to 1.2 mEq/L. Toxicity tends to begin when levels rise above roughly 1.5 mEq/L, with early signs like tremor, GI upset, and confusion, and more serious effects such as ataxia, seizures, or renal impairment at higher levels. So the level considered toxic is over 1.5. Levels like 0.8–1.0 or 0.6–1.2 are within the therapeutic range, and 0.2–0.5 is subtherapeutic. If toxicity is suspected, hold the medication, reassess symptoms and hydration, recheck the level, and notify the prescriber for further management.