A nurse is caring for a client who has been hospitalized for treatment of bipolar disorder and will be discharged with a prescription for lithium. The nurse’s discharge teaching should include information cautioning against which of the following factors that may cause lithium toxicity?

Choice A reason: Drinking green tea does not significantly contribute to lithium toxicity. Lithium is cleared renally, and green tea’s mild diuretic effect is insufficient to alter lithium levels markedly. Toxicity is driven by factors like dehydration or renal impairment, not typical beverage consumption. Choice B reason: Moderate exercise does not cause lithium toxicity, as it does not significantly alter renal clearance or blood volume. Lithium toxicity occurs with reduced excretion, often from dehydration or drug interactions, making exercise an unlikely contributor in healthy individuals. Choice C reason: Increasing sodium intake reduces lithium toxicity risk, as sodium competes with lithium for renal reabsorption, promoting lithium excretion. Higher sodium levels decrease lithium concentration in the blood, making this choice protective rather than a cause of toxicity. Choice D reason: Dehydration increases lithium toxicity risk by reducing renal clearance, concentrating lithium in the blood. Lithium is excreted by the kidneys, and low fluid volume decreases glomerular filtration rate, elevating serum lithium levels, potentially causing toxicity symptoms like tremors or confusion.