Carbamazepine

Blood

Report in 48Hrs

At Home

No Fasting Required

Details

Drug monitoring test for carbamazepine.

₹1,184₹1,691

30% OFF

Carbamazepine Test Information Guide

Why is it done?
- Measures serum levels of carbamazepine, an anticonvulsant medication used to treat seizure disorders, neuropathic pain, and bipolar disorder
- Monitors therapeutic drug levels to ensure medication efficacy while avoiding toxicity
- Ordered when initiating carbamazepine therapy to establish baseline levels
- Performed during dose adjustments to ensure optimal therapeutic range achievement
- Used to assess patient compliance and medication adherence
- Performed if seizure breakthrough occurs despite therapy
- Indicated when symptoms of toxicity are suspected (dizziness, ataxia, diplopia, nausea)
- Used during drug interaction evaluations or when other medications are added/removed
Normal Range
- Therapeutic Range: 4-12 mcg/mL (17-50 μmol/L)
- Units of Measurement: mcg/mL (micrograms per milliliter) or μmol/L (micromoles per liter)
- Below Therapeutic Range (<4 mcg/mL): Subtherapeutic levels; insufficient seizure control or symptom management may occur; dose increase may be necessary
- Within Therapeutic Range (4-12 mcg/mL): Optimal level for most patients; expected to provide seizure control or symptom relief with minimal adverse effects
- Above Therapeutic Range (>12 mcg/mL): Elevated levels indicating potential toxicity risk; neurological side effects likely; dose reduction recommended
- Critical/Toxic Level (>20 mcg/mL): Dangerous levels requiring immediate medical intervention; severe adverse effects expected
- Note: Individual therapeutic ranges may vary; some patients require levels outside the standard range for optimal control
Interpretation
- Low Levels (Below 4 mcg/mL): Indicates inadequate drug exposure; may result from non-compliance, drug interactions reducing carbamazepine metabolism, or insufficient dosing; patient education or dose escalation may be required
- Optimal Levels (4-12 mcg/mL): Therapeutic efficacy expected with acceptable tolerability; continue current dosing regimen and monitor clinically; retest in 6-12 months or if clinical circumstances change
- Mildly Elevated Levels (12-15 mcg/mL): Upper acceptable range; patient may exhibit mild side effects; consider dose reduction if adverse effects present; may be appropriate for some patients with difficult-to-control conditions
- Moderately Elevated Levels (15-20 mcg/mL): Toxic range; significant adverse effects likely including ataxia, diplopia, tremor, nystagmus, and mental changes; dose reduction strongly recommended; clinical reassessment essential
- Severely Elevated Levels (>20 mcg/mL): Critical toxicity; severe adverse effects including confusion, loss of consciousness, seizures, cardiac arrhythmias, and respiratory depression; immediate intervention required; possible hospitalization and supportive care
- Factors Affecting Results: Drug interactions (enzyme inducers/inhibitors), liver or kidney disease, age, genetic factors affecting metabolism, pregnancy status, food interactions, and specimen collection timing relative to dose administration
- Clinical Significance: Carbamazepine exhibits non-linear pharmacokinetics and auto-induction; levels may initially fall after 3-5 weeks of therapy; steady-state typically achieved in 1-2 weeks; therapeutic drug monitoring is essential for optimizing treatment
Associated Organs
- Primary Organ Systems: Central nervous system (brain), hepatic system (liver), and cardiac system (heart)
- Medical Conditions Associated with Abnormal Results: Generalized tonic-clonic seizures, focal (partial) seizures, trigeminal neuralgia, diabetic neuropathy, post-herpetic neuralgia, bipolar disorder, acute mania
- Hepatic Involvement: Carbamazepine is metabolized by liver; hepatic disease impairs metabolism leading to elevated levels; liver function monitoring recommended
- Renal Involvement: Metabolites are renally excreted; significant renal impairment may require dose adjustments
- Potential Complications from Abnormal Results: Low levels: seizure breakthrough, status epilepticus, mood destabilization; High levels: carbamazepine toxicity causing cerebellar ataxia, diplopia, nystagmus, vertigo, cardiac conduction abnormalities, severe hyponatremia, Stevens-Johnson syndrome, toxic epidermal necrolysis
- Blood-Related Effects: Carbamazepine can cause hematologic effects including leukopenia, thrombocytopenia, and aplastic anemia; baseline CBC recommended before therapy initiation
- Cutaneous Manifestations: Serious skin reactions including Stevens-Johnson syndrome and toxic epidermal necrolysis; greatest risk in first 2 months of therapy; more common in individuals with specific HLA alleles
Follow-up Tests
- Repeat Carbamazepine Levels: After dose adjustments (5-7 days); annual monitoring for stable patients; more frequently if clinical changes occur or toxicity suspected
- Complete Blood Count (CBC): Baseline before therapy; 2 weeks after initiation; then every 3 months for first year; annually thereafter to monitor for hematologic abnormalities
- Liver Function Tests (LFTs): Baseline assessment; annual screening; immediately if jaundice or hepatitis symptoms develop
- Serum Sodium and Electrolytes: Baseline and periodically; carbamazepine can cause hyponatremia; monitor if symptoms of water retention or confusion develop
- Electrocardiogram (ECG): Baseline before therapy; if cardiac symptoms develop; toxicity suspected; carbamazepine can cause cardiac conduction abnormalities
- Thyroid Function Tests (TSH, Free T4): Baseline and annually; carbamazepine induces thyroid metabolism; monitor for hypothyroidism
- Bone Density Assessment: Consider in long-term users (especially postmenopausal women and children); carbamazepine induces bone metabolism affecting vitamin D
- HLA-B*1502 Testing: Considered before therapy initiation in at-risk populations (Asian ancestry); correlates with severe cutaneous adverse reactions risk
- Vitamin D and Calcium Levels: Baseline and periodic monitoring; long-term carbamazepine use increases vitamin D metabolism; supplementation often recommended
- Clinical Seizure Monitoring: Frequent patient assessments to correlate drug levels with clinical efficacy and adverse effects
Fasting Required?
- Fasting Requirement: No - Fasting is NOT required for carbamazepine level testing
- Food Interactions: Food does not significantly interfere with carbamazepine absorption; patient may eat normally; some data suggests taking with food may reduce gastrointestinal upset
- Timing of Blood Draw: Critical for accurate interpretation; ideally drawn just before next dose (trough level) for consistent baseline measurement; generally performed 5-7 days after dose changes at steady-state achievement
- Medications and Supplements to Avoid Prior to Testing: Do NOT discontinue carbamazepine before testing; maintain regular dosing schedule; other medications should not be stopped unless directed by physician; report all current medications to laboratory
- General Patient Preparation: Maintain normal fluid intake; remain in calm state if possible (stress can slightly affect results); inform phlebotomist of current medications and supplements; continue carbamazepine dosing on regular schedule
- Specimen Requirements: Venous blood sample collected in standard serum separator tube; typically 5-10 mL required; sample processed and sent to laboratory for analysis; results usually available within 24-48 hours
- Special Circumstances: Pregnancy: Continue carbamazepine if treating serious condition; levels may decrease during pregnancy requiring monitoring; postpartum levels may increase requiring reassessment; inform laboratory of pregnancy status

How our test process works!