What is Xcopri (Cenobamate)?
Xcopri (cenobamate) is a Schedule V controlled substance antiseizure medication approved by the FDA for the treatment of partial-onset (focal) seizures in adults. 1
Mechanism of Action
Cenobamate works through a dual mechanism that distinguishes it from other antiseizure medications 2, 3:
- Blocks persistent voltage-gated sodium currents (more pronounced effect on persistent rather than transient currents)
- Acts as a positive allosteric modulator of GABAA receptors (independent of the benzodiazepine binding site)
This combination of mechanisms appears to provide broader seizure protection than medications targeting only one of these pathways 2.
Clinical Efficacy
Cenobamate has demonstrated unusually high seizure freedom rates in clinical trials 4:
- Effective across all focal seizure types (focal aware motor, focal impaired awareness, and focal to bilateral tonic-clonic seizures) 2
- In real-world studies, approximately 29% of patients achieved seizure freedom 5
- Median seizure reduction of 50% in clinical practice 5
- Maintains efficacy over long-term use 4
Dosing and Administration
1:
- Starting dose: 12.5 mg once daily
- Titration: Gradual increase over weeks (slow titration is critical to minimize adverse effects)
- Target dose: 200 mg once daily
- Maximum dose: 400 mg once daily
- Can be taken with or without food, at any time of day
- Tablets can be swallowed whole or crushed and mixed with water
Important Safety Considerations
Critical Warnings 1:
Serious allergic reactions (DRUG/DRESS syndrome):
- Can affect liver, blood cells, and other organs
- Requires immediate medical attention if rash, fever, swollen glands, or organ dysfunction develops
- Risk minimized by slow titration
QT shortening:
- Dose-dependent shortening of QTc interval (mean -11 msec at 200 mg, -18 msec at 500 mg) 1
- Contraindicated in patients with familial short QT syndrome
- Monitor for fast heartbeat or fainting
Suicidal thoughts and behavior:
- Like all antiseizure medications, carries risk of suicidal ideation (approximately 1 in 500 patients)
Abuse potential:
- Schedule V controlled substance
- Can cause euphoria at higher doses (8% at 400 mg vs 0% placebo) 1
- Physical dependence possible; requires gradual withdrawal
Common Adverse Effects 1, 3:
Most frequent (dose-related):
- Somnolence
- Dizziness
- Diplopia (double vision)
- Gait disturbances and coordination problems
- Fatigue
These effects are generally mild to moderate and often self-limiting 6.
Drug Interactions 3
Cenobamate has significant pharmacokinetic interactions:
- Inhibits CYP2C19: May require dose adjustments for lamotrigine, clobazam
- Induces CYP3A4 and CYP2B6: May require dose adjustments for carbamazepine
- Reduces effectiveness of hormonal contraceptives - alternative birth control methods recommended 1
- Non-linear pharmacokinetics: Dose increases result in disproportionally higher plasma levels, particularly above 300 mg 3
Special Populations
Renal impairment: Use with caution; dosage reduction may be needed 1
Hepatic impairment: Maximum dose 200 mg daily for mild-moderate impairment; not recommended for severe impairment 1
Pediatric use: Not FDA-approved for children, though emerging real-world evidence shows promise in pediatric drug-resistant epilepsy with 75% showing improvement and 20% achieving seizure freedom 6
Pregnancy: Unknown safety profile; patients should be enrolled in the NAAED Pregnancy Registry 1
Clinical Context
Cenobamate represents a significant therapeutic advance for adults with refractory focal epilepsy, offering higher seizure freedom rates than many established antiseizure medications 4, 2. The drug's dual mechanism of action and impressive clinical efficacy must be balanced against its complex drug interactions, need for slow titration, and potential for serious allergic reactions. The key to successful use is gradual dose escalation and careful monitoring for adverse effects, particularly during the first few months of therapy.