Before lithium begins, the nurse should verify renal function, serum electrolytes, thyroid function, vital signs, medication interactions, and pregnancy status. Lithium is cleared by the kidneys, has a narrow therapeutic range, and can impair thyroid or renal function. Serum lithium concentration is obtained after dosing begins and is monitored regularly. The other assessment groups do not address the primary pretreatment safety risks.
Clinical reasoning Changes in kidney clearance, sodium balance, hydration, or interacting medications can rapidly increase lithium exposure. Baseline renal and thyroid data allow later changes to be recognized.
Decision rule Before lithium, establish renal, electrolyte, thyroid, medication, vital-sign, and pregnancy baselines; after initiation, obtain correctly timed serum concentrations and continue organ monitoring.
Scenario A client with bipolar disorder is preparing to begin long-term lithium therapy.
Lithium monitoring — Pretreatment and ongoing assessment of serum concentration, renal function, thyroid function, electrolytes, and clinical toxicity.
Narrow therapeutic range — A small separation between concentrations that produce benefit and concentrations that cause toxicity.
Pregnancy screening — Lithium carries fetal risk, especially first trimester cardiac malformations; discuss risks and alternatives.