What laboratory tests are ordered for a patient on Carbamazepine (Tegretol)?

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From the Guidelines

For a patient on carbamazepine, baseline and periodic monitoring of complete blood count (CBC), liver function tests (LFTs), electrolytes, blood urea nitrogen (BUN), creatinine, and carbamazepine serum levels are crucial to ensure safe and effective treatment. The most recent and highest quality study 1 supports the importance of monitoring carbamazepine serum levels, with therapeutic ranges typically between 4-12 μg/mL. Key laboratory tests to order include:

  • Baseline CBC, LFTs, electrolytes, BUN, creatinine, and a pregnancy test for women of childbearing potential before starting therapy
  • Regular monitoring of carbamazepine serum levels to ensure effective dosing and avoid toxicity
  • Periodic monitoring of CBC and LFTs, especially during the first few months of treatment, to detect potential hematologic abnormalities or hepatotoxicity
  • Regular checks of sodium levels to monitor for hyponatremia
  • Consideration of thyroid function tests, as carbamazepine can affect thyroid hormone levels
  • Periodic monitoring of vitamin D, calcium, and bone density for patients on long-term therapy, as carbamazepine can affect bone metabolism. These tests are essential to minimize the risk of serious adverse effects associated with carbamazepine, including blood dyscrasias, hepatotoxicity, and electrolyte disturbances, and to ensure the best possible outcome in terms of morbidity, mortality, and quality of life 1.

From the FDA Drug Label

Monitoring of blood levels has increased the efficacy and safety of anticonvulsants ( see PRECAUTIONS, Laboratory Tests). If satisfactory clinical response has not been achieved, plasma levels should be measured to determine whether or not they are in the therapeutic range. COMPLETE PRETREATMENT HEMATOLOGICAL TESTING SHOULD BE OBTAINED AS A BASELINE If a patient in the course of treatment exhibits low or decreased white blood cell or platelet counts, the patient should be monitored closely.

The lab tests ordered for a patient on carbamazepine include:

  • Blood levels: to monitor the efficacy and safety of the medication
  • Plasma levels: to determine if the levels are within the therapeutic range
  • Pretreatment hematological testing: to obtain a baseline
  • White blood cell count: to monitor for potential bone marrow depression
  • Platelet count: to monitor for potential bone marrow depression 2 2

From the Research

Lab Tests for Patients on Carbamazepine

The following lab tests are ordered for patients on carbamazepine:

  • Serum lipid profiles, including cholesterol, LDL, HDL, VLDL, and triglycerides 3
  • Liver function tests, including bilirubin, SGPT, and alkaline phosphatase 3
  • Serum sodium levels to monitor for hyponatremia 4
  • Serum carbamazepine and carbamazepine-10,11-epoxide (CBZE) levels to monitor therapeutic drug levels 5
  • Hematological parameters, including:
    • White blood cell (WBC) count 5
    • Platelet (PLT) count 5
    • Red blood cell (RBC) count 5
    • Neutrophil (NEU%) and lymphocyte (LYM%) percentages 5
  • Biochemical parameters, including:
    • Albumin levels 5
    • Calcium and phosphorus levels 5
    • Vitamin D levels 5
  • Electrolyte concentrations, including sodium, to monitor for any potential imbalances 5

References

1
Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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