What instruction should a nurse give a client taking lithium to maintain therapeutic levels?

The recommendation to limit outdoor exercise during hot weather is essential for clients taking lithium, as it helps prevent dehydration and ensures safe therapeutic levels. Lithium can affect renal function and electrolyte balance in the body, and exposure to excessive heat or strenuous activity can lead to increased sweating and fluid loss. This can result in dehydration, which may cause lithium levels to rise dangerously high because the body has a more difficult time clearing the medication, potentially leading to toxicity. Therefore, advising clients to take appropriate measures to avoid overheating and to be mindful of hydration during hot conditions is crucial for their safety and for maintaining stable lithium levels.

In contrast, while increasing daily fluid intake may also be important for some lithium patients, it does not specifically address the risks associated with heat and exercise, making it less relevant in this case. Avoiding high-sodium foods is not generally recommended for lithium patients, as sodium intake can actually affect lithium retention in the body. Taking the medication with meals can help reduce gastrointestinal side effects, but it does not directly relate to maintaining therapeutic lithium levels under circumstances of heat exposure.