A nurse is teaching a client who has bipolar disorder about lithium. Which of the following statements should the nurse include in the teaching?

Choice A reason: Vomiting or diarrhea can lead to dehydration, which increases lithium levels in the blood, potentially causing toxicity. Instructing the client to notify their provider about these symptoms is critical for safe lithium use. Choice B reason: Decreasing fluid intake to 1 liter per day is dangerous with lithium, as adequate hydration (typically 2–3 liters daily) is needed to prevent toxicity. This is incorrect advice. Choice C reason: Excessive saliva is not a common side effect of lithium. More typical side effects include thirst, tremor, or weight gain, so this statement is inaccurate. Choice D reason: Lithium can be taken with or without food, but taking it with food may reduce stomach upset. Advising it must be taken on an empty stomach is not necessary and could discourage adherence.