When is lithium (Li) level screened in patients taking lithium (lithium carbonate)?

From the Guidelines

Lithium levels should be monitored regularly, with the frequency of monitoring depending on the stage of treatment and the patient's clinical condition, as recommended by the most recent and highest quality study 1. When initiating lithium therapy, levels should be checked twice a week during the acute phase and until the serum concentrations and clinical condition of the patient have been stabilized, according to the 2021 study 1.

Key Considerations for Lithium Level Screening

• Initially, levels should be checked 5-7 days after starting lithium or changing the dose, then weekly until levels stabilize in the therapeutic range (typically 0.6-1.2 mEq/L) 1.
• Once stable, monitoring can decrease to every 2-3 months for the first year, then every 6-12 months for maintenance therapy, as suggested by the 2014 study 1.
• Additional screening is necessary during significant illness, dehydration, when starting interacting medications (like NSAIDs, ACE inhibitors, or diuretics), or if toxicity is suspected, as noted in the 2007 study 1.
• Monitoring is crucial because lithium has a narrow therapeutic window, and levels outside this range can lead to ineffective treatment or toxicity, as highlighted in the 2021 study 1.
• Symptoms of toxicity include tremor, confusion, ataxia, and in severe cases, seizures or coma, as reported in the 2021 study 1.
• Along with lithium levels, kidney function, thyroid function, and electrolytes should be regularly assessed, as lithium can affect these systems over time, as recommended by the 2014 study 1.

Importance of Regular Monitoring

Regular monitoring of lithium levels is essential to minimize the risk of toxicity and ensure effective treatment, as emphasized in the 2021 study 1.

• The study suggests that regular monitoring of the patient’s clinical state and of serum lithium concentrations is necessary, especially during the initiation and dose adjustment phases.
• The 2014 study 1 also recommends monitoring GFR, electrolytes, and lithium levels 6 monthly or more frequently if the dose changes or the patient is acutely unwell.
• The 2007 study 1 notes that medication trials should be as systematic as possible, with the duration of trials sufficient to determine the agent's effectiveness, and that monitoring is crucial to avoid unnecessary polypharmacy.

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. N.B.: Blood samples for serum lithium determination should be drawn immediately prior to the next dose when lithium concentrations are relatively stable (i.e., 8-12 hours after the previous dose).

Lithium (Li) levels are screened in patients taking lithium:

• Twice per week during the acute phase, until the serum level and clinical condition of the patient have been stabilized.
• At least every two months in uncomplicated cases receiving maintenance therapy during remission. Lithium levels should be drawn 8-12 hours after the previous dose, immediately prior to the next dose, when concentrations are relatively stable 2.

From the Research

Lithium Level Screening

• Lithium levels are typically screened in patients taking lithium carbonate to monitor for toxicity and ensure optimal dosing 3, 4.
• The frequency of screening may vary, but it is generally recommended to monitor lithium serum levels regularly, especially when initiating treatment or changing dosages 4, 5.
• Target lithium serum levels are usually maintained between 0.6 and 0.8 mmol/L, although some studies suggest that levels should be kept within the upper range (0.8-1 mmol/L) for sustained-release preparations 4.
• Lithium levels should be drawn 12 hours after the last dose, and in patients receiving once-daily administration, the serum concentration at 24 hours should serve as the control value 4.

Factors Influencing Screening

• Age, renal function, and co-morbidities may influence the frequency and target range of lithium level screening 4, 6.
• Patients with renal impairment or those on dialysis may require more frequent monitoring and adjusted dosing regimens 7, 6.
• Pregnancy and breastfeeding may also affect lithium clearance and require closer monitoring 4.

Clinical Practice

• Health care professionals typically monitor lithium serum levels, renal function, and thyroid function regularly in patients taking lithium for bipolar disorder 5.
• However, there is variation in the monitoring of other laboratory and physical parameters, and the use of guidelines and institutional protocols may differ between prescribers 5.
• Close monitoring of pre-dialysis serum lithium concentrations is recommended for patients on dialysis, at least for two weeks after treatment initiation, to ensure therapeutic concentrations and reduce toxicity risk 7.