What is the Levetiracetam (Keppra) level?

From the Guidelines

The therapeutic range for Levetiracetam (Keppra) is generally considered to be between 12-46 μg/mL, and blood samples for level testing should ideally be drawn just before the next scheduled dose (trough level) to provide the most consistent and meaningful results. When considering the management of patients with epilepsy, monitoring Keppra levels is crucial for ensuring therapeutic effectiveness and minimizing side effects. According to the study published in the Annals of Emergency Medicine 1, the loading dose and route of administration for Levetiracetam are well established, with a recommended oral load of 1,500 mg and rapid IV loading safe and well tolerated in doses up to 60 mg/kg. Key points to consider in the management of Keppra levels include:

• The therapeutic range for Keppra is between 12-46 μg/mL, though some laboratories may use slightly different reference ranges.
• Blood samples for Keppra level testing should ideally be drawn just before the next scheduled dose (trough level) to provide the most consistent and meaningful results.
• If a patient's level is below the therapeutic range, they may experience breakthrough seizures, while levels above the range could increase the risk of side effects like dizziness, drowsiness, or behavioral changes.
• Dosage adjustments should never be made based solely on blood levels but should consider the patient's clinical response, seizure control, and presence of side effects.
• Patients with kidney impairment may require dose adjustments as Keppra is primarily eliminated through the kidneys. It is essential to note that the study 1 provides information on the loading dose and route of administration for Levetiracetam, but it does not directly address the therapeutic range for Keppra levels. However, based on general medical knowledge and the principles of therapeutic drug monitoring, the recommended therapeutic range for Keppra is widely accepted as between 12-46 μg/mL.

From the FDA Drug Label

The pharmacokinetics of levetiracetam have been studied in healthy adult subjects, adults and pediatric patients with epilepsy, elderly subjects and subjects with renal and hepatic impairment Plasma half-life of levetiracetam across studies is approximately 6 to 8 hours. Levetiracetam plasma half-life in adults is 7 ± 1 hour and is unaffected by either dose or repeated administration Levetiracetam is eliminated from the systemic circulation by renal excretion as unchanged drug which represents 66% of administered dose.

The therapeutic level of Levetiracetam is not explicitly stated in the provided drug label. However, the plasma half-life of Levetiracetam is approximately 6 to 8 hours in adults, and the peak plasma concentrations occur in about 1 hour following oral administration in fasted subjects 2.

From the Research

Levetiracetam (Keppra) Level

• The therapeutic serum concentration of Levetiracetam is 10-37 microg/mL, as reported in a case study of a 38-year-old woman who ingested 60 tablets of Levetiracetam 3.
• In postmortem cases, Levetiracetam concentrations ranged from 1.4 to 50 mg/L in patients under the age of 10, and from 190 to 35 mg/L in suicidal drug deaths 4.
• A study on brand-to-generic Levetiracetam switch in patients with epilepsy found that the mean peak plasma concentration (Cmax) was 37.8±10.4mg/L for brand Levetiracetam and 41.6±12.3mg/L for generic Levetiracetam 5.
• The recommended therapeutic concentration of Levetiracetam is typically between 6 to 18 mg/L, although individual therapeutic concentrations may vary 6.
• Levetiracetam has a low potential for drug interactions and favorable pharmacokinetic characteristics, with a rapid achievement of steady-state concentrations 7.

Factors Affecting Levetiracetam Levels

• Age, renal failure, pregnancy, and combination with other anticonvulsant drugs may affect Levetiracetam pharmacokinetics 6.
• Individual therapeutic concentrations of Levetiracetam may be useful in specific clinical situations, such as before pregnancy 6.

Clinical Significance

• Levetiracetam is effective in reducing partial seizures in patients with epilepsy, both as adjunctive treatment and as monotherapy 7.
• The most common adverse effects observed with Levetiracetam are mild and include somnolence, asthenia, and dizziness 7.
• In overdose, Levetiracetam is sedating and causes respiratory depression, but recovery is rapid with supportive care 3.