Lithium Does Increase White Blood Cell Count
Yes, lithium therapy causes leukocytosis (increased white blood cell count), which is a well-documented effect of the medication. 1, 2, 3
Mechanism and Clinical Significance
- Lithium causes an increase in circulating leukocytes (white blood cells) in the majority of patients, with a mean increase of approximately 2,200 cells/mm³ above baseline values 3
- This effect is considered a medication-related side effect rather than a sign of infection or inflammation 2
- The leukocytosis appears to be drug-related but is not dose-dependent or directly correlated with serum lithium levels 3, 4
- The FDA drug label for lithium specifically lists leukocytosis as a known side effect unrelated to dosage 1
Clinical Applications
- Lithium-induced leukocytosis has been therapeutically utilized to treat granulocytopenia (low white blood cell count) resulting from radiation and chemotherapy 5
- Clinicians have used lithium to counteract leukopenia (low white blood cell count) caused by antipsychotic medications 6
- The leukocyte-enhancing effect persists throughout long-term lithium therapy, making it potentially useful for managing certain leukopenic conditions 4
Monitoring Recommendations
- When initiating lithium therapy, baseline laboratory assessment should include complete blood cell counts 7
- Regular monitoring of white blood cell counts is recommended during lithium treatment, though this is primarily to detect potential infections rather than to monitor the leukocytosis itself 7
- If white blood cell counts decrease below 4,000/mm³ while on lithium (which would be unusual given its leukocytosis effect), this would warrant clinical attention 7
Clinical Considerations
- The leukocytosis effect of lithium is generally benign and does not require intervention or discontinuation of therapy 1, 5
- This side effect should be distinguished from leukocytosis due to infection or inflammation, which would present with other clinical symptoms 2
- When interpreting laboratory results in patients on lithium therapy, clinicians should be aware of this expected increase in white blood cell count to avoid unnecessary diagnostic workups 2
Potential Mechanisms
- Lithium acts through multiple pathways to inhibit glycogen synthetase kinase-3beta (GSK3β) 5
- It stimulates proliferation of bone marrow stem cells, which may contribute to the increased production of white blood cells 5
- Lithium enhances immunological activities of monocytes and lymphocytes while causing granulocytosis and lymphopenia 5
While lithium's effect on white blood cell count is well-documented, it's important to note that extremely elevated counts (>100,000/mm³) would not be expected from lithium alone and would warrant investigation for other causes 2.