What to monitor when on lithium (lithium carbonate) therapy?

From the Guidelines

When on lithium therapy, it is crucial to monitor blood lithium levels, kidney function tests (GFR, electrolytes), and thyroid function tests regularly, typically every 3-6 months, to minimize the risk of toxicity and ensure therapeutic efficacy. This monitoring is essential due to lithium's narrow therapeutic window and its potential to cause nephrotoxicity and thyroid dysfunction 1. The monitoring should include:

• Blood lithium levels to maintain therapeutic levels between 0.6-1.2 mEq/L
• Kidney function tests, including GFR, creatinine, and electrolytes, to detect any signs of nephrotoxicity
• Thyroid function tests, including TSH and T4, to monitor for thyroid dysfunction
• Electrolytes, particularly sodium levels, to prevent lithium toxicity
• Weight, blood pressure, and blood glucose monitoring to detect metabolic changes

It is also important for patients to be aware of the signs of lithium toxicity, such as tremor, confusion, slurred speech, vomiting, diarrhea, and unsteady gait, and to seek immediate medical attention if these symptoms occur 1. Additionally, patients should inform all healthcare providers about their lithium use, especially before starting new medications that may interact with lithium, such as NSAIDs, diuretics, and certain antibiotics. Maintaining consistent salt and water intake is also crucial to prevent sudden changes in lithium levels. Regular monitoring and patient education are key to minimizing the risks associated with lithium therapy and ensuring its effectiveness.

From the FDA Drug Label

DOSAGE AND ADMINISTRATION ... Regular monitoring of the patient’s clinical state and of serum lithium levels is necessary. Serum levels should be determined twice per week during the acute phase, and until the serum level and clinical condition of the patient have been stabilized. Serum lithium levels in uncomplicated cases receiving maintenance therapy during remission should be monitored at least every two months. The key things to monitor when on lithium therapy are:

• Serum lithium levels:
  • Twice per week during the acute phase
  • At least every two months during maintenance therapy
• Clinical state of the patient 2

From the Research

Monitoring Parameters

When on lithium (lithium carbonate) therapy, the following parameters should be monitored:

• Serum lithium levels: The therapeutic range is generally considered to be between 0.6 and 1.0 mmol/L 3, 4, 5, 6
• Renal function: Lithium is almost exclusively excreted via the kidney, and renal insufficiency can lead to a decrease in lithium clearance 4
• Thyroid function: Lithium can affect thyroid function, and regular monitoring is recommended 3, 4, 7

Monitoring Frequency

The frequency of monitoring depends on various factors, including the patient's age, renal function, and medical history. Generally, the following monitoring frequencies are recommended:

• Serum lithium levels: Every 3 to 6 months 3, 6, 7
• Renal function: Every 3 to 6 months 3, 7
• Thyroid function: Every 6 months 3

Special Considerations

Certain patient populations may require more frequent monitoring, such as:

• Older adults: More frequent monitoring is recommended due to the increased risk of adverse events 7
• Pregnant women: Lithium clearance increases during pregnancy, and more frequent monitoring is recommended 4
• Patients with renal insufficiency: More frequent monitoring is recommended due to the decreased lithium clearance 4