A nurse is providing discharge teaching to a client who has bipolar disorder and will be discharged with a prescription for lithium. The nurse should teach the client that which of the following factors puts her at risk for lithium toxicity?

Choice A reason: Drinking 2 liters of liquids daily supports hydration, reducing lithium toxicity risk by promoting renal excretion. Lithium is cleared by the kidneys, and adequate fluid intake prevents concentration, making this choice incorrect. Choice B reason: Tyramine is relevant to MAOI antidepressants, causing hypertensive crises, not lithium. Lithium toxicity is related to renal clearance and electrolyte balance, not dietary tyramine, making this choice incorrect for lithium risks. Choice C reason: Running 4 miles outdoors daily causes significant fluid loss through sweat, reducing blood volume and impairing lithium excretion by the kidneys. This increases lithium concentration, risking toxicity, making this the correct risk factor. Choice D reason: Eating 2–3 gm of sodium daily is within normal limits and helps maintain electrolyte balance, aiding lithium excretion. Low sodium increases lithium retention, but this amount is not a risk, making this choice incorrect.