Lab Work for Patients Taking Keppra (Levetiracetam)
Routine laboratory monitoring is not required for patients on levetiracetam, as it does not cause clinically significant hematologic or hepatic abnormalities that necessitate regular testing. 1
Baseline Laboratory Assessment
When initiating levetiracetam therapy, consider obtaining:
- Complete Blood Count (CBC) - Minor decreases in WBC (mean –0.4 × 10⁹/L) and neutrophil counts (mean –0.3 × 10⁹/L) have been observed, though these are statistically significant but not clinically meaningful 1
- Liver Function Tests (LFTs) - No meaningful changes occur in controlled trials, with LFT abnormalities similar between levetiracetam (1.4%) and placebo groups 1
- Pregnancy test - For women of childbearing age, as this affects treatment decisions and monitoring 2
- Renal function (creatinine clearance) - Essential for dose adjustment, as levetiracetam is primarily renally eliminated and requires dosing modifications in renal impairment 3
Ongoing Monitoring Requirements
No routine laboratory monitoring is necessary during maintenance therapy with levetiracetam. 1 This represents a significant advantage over older antiepileptic drugs.
When to Consider Laboratory Testing
Obtain labs only if clinically indicated by:
- New symptoms suggesting hematologic abnormalities - Though only 3.2% of patients develop possibly significant decreased WBC (≤2.8 × 10⁹/L) versus 1.8% on placebo, and no patients required discontinuation 1
- Signs of hepatotoxicity - Though hepatic abnormalities are rare, with only 1 patient (0.07%) discontinued for LFT abnormalities in clinical trials 1
- Breakthrough seizures - Check serum glucose and sodium, as these are the most common metabolic causes of seizures 2
- Suspected non-compliance - Levetiracetam levels can be obtained, though therapeutic drug monitoring is not routinely recommended due to lack of correlation between serum levels and efficacy 4
Key Clinical Advantages
Levetiracetam's favorable laboratory profile includes:
- No cytochrome P450 enzyme induction - Minimal drug-drug interactions with other medications 1, 5
- No effect on oral contraceptive efficacy - Does not alter ethinyl estradiol or levonorgestrel levels 1
- No clinically significant protein binding - Less than 10% bound, eliminating concerns about displacement interactions 1
- No requirement for cardiac monitoring - Unlike phenytoin/fosphenytoin which require continuous ECG monitoring 3
Common Pitfall to Avoid
Do not order routine "antiepileptic drug levels" or serial CBCs/LFTs in stable patients on levetiracetam. This represents unnecessary testing that adds cost without clinical benefit, as the drug's safety profile does not warrant such monitoring. 1 Focus instead on clinical assessment for behavioral changes, somnolence, and seizure control. 1, 5