Which of the following represents the therapeutic lithium range?

• A. 0.4-0.8
• B. 0.6-1.2
• C. 1.2-2.0
• D. 2.0-2.5

Answer: (B)

Lithium works best when kept in a very narrow range in the blood, so levels are closely monitored to balance effectiveness with safety. The typical therapeutic range is 0.6 to 1.2 mEq/L. Staying within this window allows mood stabilization with tolerable side effects; if levels fall below this, the medication is often not effective in preventing mood swings. If levels rise above this range, the risk of toxicity increases, leading to symptoms such as tremor, confusion, unsteady gait, nausea or vomiting, and can progress to more serious neurologic or renal problems.

Because of the narrow window, regular blood tests are essential, along with consistent hydration and steady salt intake, since changes in kidney function and sodium levels can shift lithium levels. Levels are usually checked about 12 hours after a dose (a trough level) to accurately assess the current amount in the bloodstream.