The nurse is reviewing baseline laboratory monitoring for a … | MyMerci
Medical EmergenciesPA
Question
The nurse is reviewing baseline laboratory monitoring for a client newly prescribed long-term lithium therapy. Which set of tests is most important before and during therapy?
1Only liver enzymes because lithium is primarily metabolized by the liver.
2Creatinine/BUN, electrolytes, TSH, pregnancy status when applicable, and serum lithium levels.✓ Correct answer
3Peak lithium levels 30 minutes after each dose and daily platelet counts.
4Weekly troponin and BNP because lithium commonly causes myocardial infarction.
Explanation
Lithium is not hepatically metabolized; it is primarily renally cleared and can affect thyroid function. Baseline and ongoing monitoring should include renal function, electrolytes/sodium, thyroid function, pregnancy status when relevant, and scheduled serum lithium levels.
In-depth explanation
Clinical Practice Guide Before chronic lithium: check kidney function, sodium/electrolytes, thyroid status, pregnancy status when relevant, and establish a monitoring plan for 12-hour trough levels.
Clinical scenario
Scenario New long-term lithium prescription; baseline safety labs needed.
Key concepts
Renal function — Reduced GFR decreases lithium clearance and raises toxicity risk; monitor creatinine/BUN and hydration status.
Thyroid function — Lithium can cause hypothyroidism and goiter; monitor TSH and symptoms such as fatigue, weight gain, and cold intolerance.
Pregnancy screening — Lithium carries fetal risk, especially first trimester cardiac malformations; discuss risks and alternatives.