Which statement best describes lithium clearance?

Which statement best describes lithium clearance?

• A. It is cleared by the liver
• B. It is cleared renally
• C. It is cleared by the lungs
• D. It is not cleared and accumulates

Answer: (B)

Lithium is eliminated primarily by the kidneys. It is not metabolized by the liver, and the kidneys filter and excrete lithium in urine. Some lithium is reabsorbed in the proximal tubule along with sodium, so any factors that affect sodium handling or kidney function can alter lithium clearance. Because the renal route is responsible for removing lithium from the body, statements describing its clearance as renal are the most accurate. In contrast, the liver and lungs do not play a major role in lithium elimination, and saying it isn’t cleared and simply accumulates isn’t generally true unless kidney function is impaired.

Lithium is eliminated primarily by the kidneys. It is not metabolized by the liver, and the kidneys filter and excrete lithium in urine. Some lithium is reabsorbed in the proximal tubule along with sodium, so any factors that affect sodium handling or kidney function can alter lithium clearance. Because the renal route is responsible for removing lithium from the body, statements describing its clearance as renal are the most accurate. In contrast, the liver and lungs do not play a major role in lithium elimination, and saying it isn’t cleared and simply accumulates isn’t generally true unless kidney function is impaired.