From the Guidelines
Lithium levels should be checked at least every 6 months, or more frequently if the dose changes or the patient is acutely unwell. This recommendation is based on the 2014 study by the American Journal of Kidney Diseases 1, which emphasizes the importance of monitoring GFR, electrolytes, and lithium levels in patients taking lithium. The study highlights the potential for lithium to cause renal tubular dysfunction and nephrotoxicity, even at therapeutic levels, and stresses the need for regular monitoring to minimize these risks.
Key considerations for lithium monitoring include:
- Checking GFR, electrolytes, and lithium levels every 6 months, or more frequently if the dose changes or the patient is acutely unwell
- Avoiding the use of concomitant NSAIDs, which can increase the risk of lithium toxicity
- Maintaining hydration during intercurrent illness to prevent dehydration and electrolyte imbalances
- Weighing the risk-benefit of lithium therapy in specific situations, particularly in patients with pre-existing kidney disease or other comorbidities
It is essential to note that the frequency of lithium monitoring may need to be adjusted based on individual patient factors, such as changes in kidney function, medication regimen, or overall health status. Regular monitoring is crucial to ensure that lithium levels remain within the therapeutic range and to minimize the risk of toxicity or other adverse effects. As noted in the study, the risk-benefit of lithium therapy must be carefully weighed in each patient, taking into account the potential benefits of therapy as well as the potential risks 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.
- Frequency of lithium level checks:
- During the acute phase: twice per week
- During maintenance therapy: at least every two months 2
From the Research
Frequency of Lithium Level Checks
- The frequency of lithium level checks is crucial to prevent serious adverse events, particularly in older patients 3.
- A study published in 2018 recommended lithium level and renal monitoring every 3 months in older patients treated with lithium 3.
- However, another study published in 2021 suggested that the monitoring interval could be extended to 6 months in some cases, particularly for patients who have achieved 12 months of lithium tests within the target range (0.40-0.79 mmol/L) 4.
- For patients with lithium levels between 0.80-0.99 mmol/L, the test interval should remain at 3 months 4.
Renal Function Monitoring
- Renal function monitoring is also essential when taking lithium, as it can cause long-term organ toxicity 5.
- A study published in 1999 recommended monitoring serum creatinine levels on a yearly basis and getting further medical evaluation when the serum creatinine level consistently rises above 140 mmol/L (1.6 mg/dl) 5.
- Another study published in 2021 found that 3 monthly testing was associated with 90% of lithium results remaining within range, compared with 85% at 6 monthly intervals 4.
Individualized Monitoring
- The frequency of lithium level checks and renal function monitoring may need to be individualized based on patient factors, such as age and duration of lithium therapy 4.
- However, a study published in 2021 found that neither age nor duration of lithium therapy had any significant effect on lithium level stability 4.