What are key monitoring parameters for lithium therapy in mood disorders?

• A. Therapeutic plasma level (0.6–1.2 mEq/L); renal function; thyroid function; hydration status; signs of toxicity; and monitor drug interactions.
• B. Only liver enzymes.
• C. Blood pressure and heart rate.
• D. Glucose tolerance only.

Answer: (A)

Lithium therapy requires careful, ongoing monitoring because it has a very narrow range between helpful and harmful effects and is cleared by the kidneys. The best monitoring plan includes checking the therapeutic plasma level to keep it roughly within 0.6–1.2 mEq/L for mood stabilization while avoiding toxicity. Because lithium is eliminated by the kidneys, regular assessment of renal function is essential to catch any decline that could let lithium accumulate. Lithium can also affect the thyroid, so thyroid function tests are needed to detect potential hypothyroidism that can develop with long-term use. Hydration and salt balance directly influence lithium levels—dehydration or low sodium can raise lithium levels—so monitoring hydration status and maintaining consistent fluid and salt intake is important. Early signs of toxicity, such as tremor, confusion, ataxia, and GI symptoms, should be watched for and addressed promptly. Since drug interactions can alter lithium levels, keeping an eye on potential interacting medications is crucial to prevent unexpected increases or decreases in lithium. These elements together address both the effectiveness and safety of therapy; focusing on only liver enzymes, or only vital signs, or only glucose tolerance would miss these specific risks.