Serum Lithium Monitoring After Initiation
Serum lithium levels should be checked twice per week during the acute phase until the serum concentrations and clinical condition have stabilized, with the first check occurring within 4-7 days after initiating therapy. 1, 2
Recommended Monitoring Schedule
- Initial serum lithium level should be checked within 4-7 days after starting lithium therapy 1, 2
- Subsequent monitoring should occur twice per week during the acute phase until stabilization 1, 2
- Blood samples should be drawn 12 hours after the last dose (trough level) when lithium concentrations are relatively stable 1, 3
- After stabilization, monitoring can be reduced to every 2 months for maintenance therapy 1
Factors Affecting Monitoring Frequency
- Higher risk patients may require more frequent monitoring:
Target Serum Lithium Levels
- For acute mania: 1.0-1.5 mEq/L 1
- For long-term maintenance: 0.6-1.2 mEq/L 1
- Some evidence suggests that maintenance levels between 0.8-1.0 mEq/L may be more effective than lower ranges (0.4-0.6 mEq/L) 4
Common Pitfalls to Avoid
- Failing to establish baseline renal function before initiating lithium therapy 2
- Not drawing blood samples at the correct time (should be 12 hours after last dose) 1, 3
- Overlooking the need for more frequent monitoring if symptoms of toxicity appear 2
- Not adjusting monitoring frequency during intercurrent illness or when starting interacting medications 2
Special Considerations
- Sustained-release formulations have different peak times (4-5 hours vs 1-2 hours for standard release) 3
- Lithium should be temporarily suspended during intercurrent illness, planned IV radiocontrast administration, bowel preparation, or prior to major surgery 2
- Early signs of lithium toxicity include tremor, nausea, diarrhea, and polyuria-polydipsia 5
Remember that accurate patient evaluation requires both clinical assessment and laboratory analysis, and total reliance should not be placed on serum levels alone 1.