1. Clinical Overview
Levetiracetam is a second-generation antiepileptic drug (AED) belonging to the racetam class. It is a pyrrolidone derivative with a unique mechanism of action, distinct from other AEDs. It is widely used as monotherapy or adjunctive therapy for the management of focal (partial-onset) seizures with or without secondary generalization, myoclonic seizures, and primary generalized tonic-clonic seizures. It is characterized by favorable pharmacokinetics, including rapid and complete absorption, linear kinetics, minimal protein binding, and a low potential for drug-drug interactions.
| Onset | Duration | Bioavailability |
|---|---|---|
| Steady-state plasma concentrations are achieved within 2 days of twice-daily dosing. | Approximately 12 hours, necessitating twice-daily dosing. | >95% |
2. Mechanism of Action
The exact mechanism is not fully elucidated but is distinct from other antiepileptic drugs. It does not act on traditional targets like sodium channels, GABA, or glutamate receptors. Its primary action is believed to be modulation of synaptic neurotransmitter release via binding to the synaptic vesicle protein 2A (SV2A).
3. Indications & Uses
- Adjunctive therapy in the treatment of partial-onset seizures with or without secondary generalization in adults and children from 1 month of age.
- Adjunctive therapy in the treatment of myoclonic seizures in adults and adolescents from 12 years of age with Juvenile Myoclonic Epilepsy.
- Adjunctive therapy in the treatment of primary generalized tonic-clonic seizures in adults and children from 6 years of age with Idiopathic Generalized Epilepsy.
- Monotherapy in the treatment of partial-onset seizures with or without secondary generalization in patients from 16 years of age.
4. Dosage & Administration
Adult Dosage: Adjunctive Therapy: Start at 500 mg twice daily (1000 mg/day). Can be increased by 500 mg twice daily every 2-4 weeks. Effective dose range: 1000-3000 mg/day. Monotherapy: Start at 250 mg twice daily, titrate to 500 mg twice daily after 2 weeks.
Administration: Tablets can be taken with or without food. Swallow whole with a glass of water. Do not crush or chew unless specified (e.g., oral solution). For patients unable to swallow, tablets can be dispersed in a small amount of water immediately before use. Maintain consistent dosing schedule.
5. Side Effects
Common side effects may include:
- Somnolence (drowsiness)
- Asthenia (fatigue, weakness)
- Headache
- Dizziness
- Nasopharyngitis
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Other CNS Depressants (e.g., Alcohol, Benzodiazepines, Opioids, Barbiturates) | Additive CNS depression, increased risk of somnolence, dizziness, and impaired coordination. | Moderate |
| Probenecid | Inhibits renal tubular secretion of the primary inactive metabolite, increasing its plasma levels. Clinical significance for levetiracetam itself is minimal. | Minor |
| Methotrexate | May reduce renal clearance of methotrexate's primary metabolite, 7-hydroxymethotrexate. Monitor for methotrexate toxicity. | Moderate |
| Oral Contraceptives (Ethinyl Estradiol, Levonorgestrel) | No clinically significant pharmacokinetic interaction. Contraceptive efficacy is not reduced. | None |
7. Patient Counselling
- DO take the medicine exactly as prescribed, at the same times each day.
- DO NOT stop taking levetiracetam suddenly; this can cause increased seizures (status epilepticus). Always taper under doctor's supervision.
- DO inform all your doctors and dentists that you are taking this medicine.
- DO NOT consume alcohol while on this medication.
- DO keep a seizure diary to track frequency and side effects for doctor review.
8. Toxicology & Storage
Overdose: Somnolence, agitation, aggression, depressed level of consciousness, respiratory depression, and coma. Doses up to 6000 mg/day have been reported with minimal effects.
Storage: Store at room temperature (15°C to 30°C). Protect from moisture. Keep in the original blister pack or container. Keep out of reach and sight of children. Do not use after the expiry date printed on the pack.