What should be monitored closely in a patient taking Lithium?

Patients taking Lithium require close monitoring of sodium levels because Lithium's mechanism of action is closely tied to sodium's presence in the body. Lithium is a mood stabilizer commonly used to treat bipolar disorder, and it can mimic sodium in terms of how it is processed in the kidneys. An increase or decrease in sodium levels can significantly affect Lithium concentration in the bloodstream.

Low sodium levels (hyponatremia) can lead to an increase in Lithium levels, heightening the risk of Lithium toxicity. Conversely, high sodium levels can lead to decreased Lithium levels, potentially worsening the patient's psychiatric symptoms. Therefore, monitoring sodium levels is critical for adjusting Lithium dosage and ensuring the patient is receiving effective treatment without the risks associated with toxicity or under-treatment. This critical relationship underscores the need for regular monitoring in patients on Lithium therapy.