Which organ is at the highest risk of Lithium toxicity?

Which organ is at the highest risk of Lithium toxicity?

• A. Liver
• B. Kidneys
• C. Heart
• D. Lungs

Answer: (B)

Lithium is cleared by the kidneys, so the kidneys are the organ most at risk of lithium toxicity. It isn’t metabolized by the liver, and while it can affect multiple systems at high levels, the toxicity most strongly tied to its use is renal. Lithium is filtered and then reabsorbed in the proximal tubule in a process that mirrors sodium handling; factors that reduce kidney clearance—like dehydration or impaired renal function—increase lithium levels and the chance of toxicity. This makes the kidneys the primary concern for toxicity, with clinical signs often centered on kidney-related issues such as polyuria, polydipsia, or more general signs of elevated lithium levels. Monitoring renal function and ensuring adequate hydration are key to preventing toxicity.

Lithium is cleared by the kidneys, so the kidneys are the organ most at risk of lithium toxicity. It isn’t metabolized by the liver, and while it can affect multiple systems at high levels, the toxicity most strongly tied to its use is renal. Lithium is filtered and then reabsorbed in the proximal tubule in a process that mirrors sodium handling; factors that reduce kidney clearance—like dehydration or impaired renal function—increase lithium levels and the chance of toxicity. This makes the kidneys the primary concern for toxicity, with clinical signs often centered on kidney-related issues such as polyuria, polydipsia, or more general signs of elevated lithium levels. Monitoring renal function and ensuring adequate hydration are key to preventing toxicity.