Which of the following is an early sign of lithium toxicity that the patient should report?

• A. Confusion and coarse hand tremors.
• B. Weight gain and fatigue.
• C. Drowsiness and dry mouth.
• D. Nausea.

Answer: (A)

Lithium has a narrow therapeutic range, so small increases in its level can quickly lead to toxicity. The earliest neurotoxic signs to watch for are a coarse hand tremor and confusion. Reporting these symptoms promptly allows the clinician to check the lithium level and adjust the dose or hydration to prevent progression to more serious toxicity, such as ataxia, seizures, or coma. Weight gain and fatigue are more chronic, long-term side effects and don’t indicate an acute rise in lithium. Drowsiness and dry mouth can occur with normal dosing or dehydration but are not specific early warning signs of lithium toxicity. Nausea can occur at therapeutic levels and is not a reliable early indicator of toxicity.