What are the indications for measuring Levetiracetam (Keppra) levels?

From the Guidelines

Levetiracetam level monitoring is generally not routinely indicated for most patients, but may be useful in specific situations such as suspected non-adherence, pregnancy, renal impairment, unexpected toxicity, and status epilepticus. When monitoring is performed, the therapeutic range is typically considered to be 12-46 μg/mL, though this is less strictly defined than for other antiepileptic drugs, as seen in the context of loading doses and administration strategies for antiepileptic medications in the emergency department setting 1. Some key points to consider when deciding on levetiracetam level monitoring include:

• Suspected non-adherence to medication: levels may help confirm whether the patient is taking their medication as prescribed
• Pregnancy: levels may decrease requiring dose adjustments to maintain therapeutic efficacy
• Renal impairment: as levetiracetam is primarily excreted unchanged by the kidneys, levels may be affected in patients with renal impairment
• Unexpected toxicity: despite standard dosing, levels may help identify patients experiencing adverse effects
• Status epilepticus: rapid achievement of therapeutic levels is critical in this situation It's also important to note that levetiracetam has a favorable pharmacokinetic profile, including linear kinetics, minimal protein binding, and lack of hepatic metabolism, which makes routine therapeutic drug monitoring less necessary compared to other antiepileptic medications, as discussed in the context of antiepileptic medication loading in the emergency department 1. In terms of administration, a loading dose of 1,500 mg oral load or rapid IV loading safe and well tolerated in doses up to 60 mg/kg can be considered, with no seizures within 24 h of loading in a study of oral loading 1. Overall, levetiracetam level monitoring should be individualized based on patient-specific factors and clinical context, taking into account the medication's pharmacokinetic properties and the specific situation, such as the emergency department setting discussed in the study 1.

From the FDA Drug Label

The FDA drug label does not answer the question.

From the Research

Indications of Levetiracetam Level

The indications of levetiracetam level can be understood through its various approved uses and pharmacokinetic properties.

• Levetiracetam is approved as adjunctive treatment of partial-onset seizures with or without secondary generalization, monotherapy treatment of partial-onset seizures with or without secondary generalization, and adjunctive treatment of myoclonic seizures associated with juvenile myoclonic epilepsy and primary generalized tonic-clonic (GTC) seizures associated with idiopathic generalized epilepsy 2, 3.
• The drug has a novel structure and unique mechanisms of action, involving neuronal binding to synaptic vesicle protein 2A, inhibiting calcium release from intraneuronal stores, and opposing the activity of negative modulators of GABA- and glycin-gated currents 2, 3.
• Levetiracetam is associated with rapid and complete absorption, high oral bioavailability, minimal metabolism, and primarily renal elimination, which contributes to its efficacy in controlling seizures 2, 3.
• The efficacy of levetiracetam in controlling seizures has been established in numerous randomized, double-blind, controlled, multicentre trials in patients with epilepsy, including adjunctive therapy in patients with refractory partial-onset seizures and monotherapy in patients with newly diagnosed partial-onset seizures 2, 3.
• Levetiracetam has also been evaluated in various studies conducted in the critical care setting for the treatment of status epilepticus, stroke-related seizures, seizures following subarachnoid or intracerebral hemorrhage, post-traumatic seizures, tumor-related seizures, and seizures in critically ill patients 4.
• Therapeutic monitoring of levetiracetam plasma concentrations is important to help maintain seizure control in women with epilepsy during pregnancy, as pharmacokinetic changes associated with pregnancy may increase apparent clearance of extended-release formulations of levetiracetam 5.
• Levetiracetam has been found to be effective in the treatment of idiopathic generalized epilepsies, including generalized tonic-clonic seizures and myoclonus, and may be considered as an alternative to valproate in women of childbearing age due to its lower teratogenic potential 6.