Levetiracetam
Levetiracetam is an anticonvulsant medication used primarily in the treatment of epilepsy. It is effective for treating both focal (partial) seizures and generalized seizures, including tonic-clonic and myoclonic seizures. Levetiracetam is known for its relatively favorable side effect profile and is often used as an adjunctive therapy or in combination with other anticonvulsants.
Trade Name
Levetiracetam is marketed under the brand name Keppra.
Chemical Properties
Chemical structure: Levetiracetam is a pyrrolidine derivative.
Molecular formula: C₆H₉N₄O₂
Molecular weight: 170.17 g/mol
Solubility: Levetiracetam is highly soluble in water and is available in oral and intravenous formulations.
Biochemical Properties
Mechanism of action: The exact mechanism of action of levetiracetam is not fully understood, but it is believed to act by binding to a specific protein called SV2A (synaptic vesicle protein 2A), which is involved in the release of neurotransmitters. This binding inhibits excessive neurotransmitter release and stabilizes neuronal activity, which helps prevent seizures. Unlike many other anticonvulsants, levetiracetam does not rely on the modulation of GABA or sodium channels.
Pharmacology
Administration: Levetiracetam is administered orally in the form of tablets, liquid solution, or as an intravenous injection in hospital settings.
Bioavailability: Levetiracetam has near-complete bioavailability (approximately 100%) when taken orally, making it very effective.
Metabolism: Levetiracetam is minimally metabolized in the liver and does not significantly affect liver enzymes, which results in fewer drug interactions compared to many other anticonvulsants. The majority of the drug is excreted unchanged in the urine.
Half-life: The half-life of levetiracetam is approximately 6–8 hours, which allows for twice-daily dosing in most patients.
Clinical Indications
Epilepsy: It is effective in the treatment of both focal and generalized seizures, including tonic-clonic seizures, myoclonic seizures, and partial seizures. It is commonly used as adjunctive therapy but can also be used as monotherapy in some cases.
Other uses: Levetiracetam may be used off-label for conditions such as neuropathic pain, migraine prophylaxis, or anxiety disorders, though these are less common indications.
Side Effects
Drowsiness and fatigue: Some people experience sedation or tiredness, especially when starting treatment or increasing the dose.
Dizziness: Light-headedness or unsteadiness can occur, particularly when standing up quickly.
Irritability or mood changes: Some individuals may experience mood swings, irritability, or aggression.
Cognitive effects: Levetiracetam can cause problems with concentration, memory, or attention, although these effects are usually mild and tend to improve over time.
Headache: Some patients report headaches while taking levetiracetam.
Gastrointestinal issues: Nausea, vomiting, and diarrhea can occur, especially when first starting treatment.
Skin rashes: Rashes can occur, and in rare cases, may develop into more severe reactions, including Stevens-Johnson syndrome.
Behavioral changes: Rarely, some people may experience more serious psychiatric effects such as depression, anxiety, or suicidal thoughts.
Monitoring and Considerations
Dose adjustments: Levetiracetam is typically started at a low dose and gradually increased to minimize side effects. Dosage adjustments may be required in patients with renal impairment, as the drug is excreted mainly through the kidneys.
Pregnancy: Levetiracetam is classified as Category C during pregnancy, which means its use should be avoided unless clearly needed, as the potential risks to the fetus are not well established. It is considered one of the safer anticonvulsants during pregnancy, but it should still only be used when the benefits outweigh the risks.
Drug interactions: Levetiracetam has a relatively low potential for drug interactions because it does not significantly affect the cytochrome P450 enzyme system. However, it can interact with other medications that are primarily cleared by the kidneys or central nervous system depressants.
Levetiracetam is a highly effective and generally well-tolerated anticonvulsant used in the treatment of epilepsy. It offers the benefit of fewer drug interactions compared to other anticonvulsants and has a convenient dosing schedule. However, it can cause side effects such as drowsiness, mood changes, and cognitive disturbances, which should be monitored, especially in the early stages of treatment.
