How often should lithium (lithium) levels be checked?

From the Guidelines

Lithium levels should be checked every 6 months or more frequently if the dose changes or the patient is acutely unwell. This recommendation is based on the most recent and highest quality study available, which emphasizes the importance of regular monitoring to minimize the risk of nephrotoxicity and renal tubular dysfunction associated with lithium therapy 1.

Key Considerations

• Monitoring should include GFR, electrolytes, and lithium levels to ensure early detection of potential adverse effects.
• Concomitant use of NSAIDs should be avoided, and patients should be advised to maintain hydration during intercurrent illness.
• The risk-benefit of lithium therapy must be carefully weighed in each individual case, taking into account the patient's medical history, comorbidities, and other medications.

Frequency of Monitoring

• For stable patients on maintenance therapy, monitoring every 6 months is generally recommended.
• More frequent monitoring (e.g., every 1-3 months) may be necessary for patients with medical comorbidities, those taking interacting medications, or during dose adjustments.
• Blood samples should be drawn 12 hours after the last dose to obtain accurate trough levels, typically in the morning before the first dose of the day.

Therapeutic Range and Toxicity

• The therapeutic range for lithium is typically 0.6-1.2 mEq/L, with lower targets (0.6-0.8 mEq/L) often used for maintenance therapy.
• Signs of toxicity can appear at levels above 1.5 mEq/L, and severe toxicity can occur above 2.0 mEq/L, potentially causing seizures, coma, or death. By following these guidelines and prioritizing regular monitoring, healthcare providers can minimize the risks associated with lithium therapy and optimize treatment outcomes for patients with bipolar disorder or other conditions requiring lithium treatment 1.

From the FDA Drug Label

DOSAGE AND ADMINISTRATION ... 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.

• Acute phase: Check lithium levels twice per week.
• Maintenance therapy: Check lithium levels at least every two months 2.

From the Research

Monitoring Lithium Levels

• The frequency of checking lithium levels is crucial to prevent serious adverse events, especially in older patients 3.
• It is recommended to monitor lithium levels and renal function every 3 months in older patients treated with lithium 3.
• However, a study found that lithium monitoring was infrequent and inconsistent with international standards, with only 24.1% of lithium users having at least one serum lithium concentration recorded within 90 days of follow-up 3.
• Another study found that just over one seventh (16%) of patients had been monitored in compliance with the guidelines for all three parameters (lithium serum levels, creatinine, and thyroid-stimulating hormone) during total follow-up 4.

Factors Affecting Monitoring Frequency

• Patient characteristics such as age, sex, and presence of interacting co-medication can affect the frequency of monitoring 4.
• Patients receiving prescriptions solely from general practitioners, prevalent users of lithium, and patients without other days with laboratory measurements had been monitored less frequently in compliance with the guidelines 4.
• Collaboration between psychiatrist, nephrologist, and patients themselves is essential for effective monitoring and management of lithium therapy 5.

Importance of Monitoring

• Monitoring lithium levels and renal function is necessary to prevent lithium-induced nephrogenic diabetes insipidus (Li-NDI) and lithium nephropathy (Li-NP) 5.
• Early diagnosis and treatment can prevent further progression and permanent damage 5.
• Lithium-induced nephrotoxicity is characterized by interstitial nephritis with microcyst formation and occasional focal segmental glomerulosclerosis, and can be prevented by using a once-daily dosing schedule and targeting the lowest serum lithium level that is effective 5, 6.