Cenobamate is an effective novel antiepileptic drug, but it is associated with a range of side effects.

I. Side Effects of Cenobamate

1. Most Common Side Effects (Incidence ≥10% and higher than placebo)

Clinical studies have shown the most frequent side effects include somnolence, dizziness, fatigue, diplopia, and headache. These reactions are dose-dependent, with higher incidence at higher doses.

2. Neurological Side Effects (Dose-dependent)

(1) Somnolence and fatigue.

(2) Dizziness and balance disturbances.

(3) Cognitive impairment: memory deficits, poor concentration, confusion, speech disorders, etc.

(4) Visual disturbances: diplopia, blurred vision.

3. Severe Adverse Reactions (Requiring Vigilance)

(1) DRESS syndrome: Drug Reaction with Eosinophilia and Systemic Symptoms, which can be fatal. Risk increases with rapid dose titration; manifestations include fever, rash, lymphadenopathy, facial swelling, and may be accompanied by hepatitis, nephritis, myocarditis, etc.

(2) Hepatic injury: Post-marketing reports of acute liver failure requiring liver transplantation. Transaminase elevations are dose-related (2.7% of patients in the 400 mg group had ALT >3× upper limit of normal).

(3) QT interval shortening: May increase the risk of cardiac arrhythmias.

(4) Suicidal ideation and behavior: The overall risk with antiepileptic drugs is approximately 1 in 500; close monitoring of mood and behavioral changes is required.

(5) Hyperkalemia: Elevated serum potassium was observed in some patients in the 400 mg group.

4. Post-marketing Adverse Reactions

Including psychotic disorders (hallucinations, delusions/paranoia), hostile behavior, aggressive behavior, and liver failure.

II. Strategies for Alleviating Side Effects

1. Strict Adherence to Titration Schedule

(1) Side effects are closely related to the rate of dose escalation.

(2) Fatal cases of DRESS syndrome have occurred with weekly or more rapid dose increases.

(3) The recommended regimen must be strictly followed: starting at 12.5 mg once daily, with dose increments every two weeks; no accelerated titration is permitted.

2. Management of Somnolence and Fatigue

(1) Avoid driving, operating machinery, or engaging in hazardous activities after dosing until individual response is established.

(2) Avoid concomitant use with alcohol or other central nervous system depressants (e.g., sedatives, hypnotics) to prevent worsening somnolence.

(3) Consider bedtime administration (after consulting a physician) to reduce daytime drowsiness.

3. Management of Dizziness and Balance Disturbances

(1) Move slowly when getting up or changing posture.

(2) Avoid sudden standing to prevent falls.

(3) If symptoms are severe (approximately 5% of patients discontinued treatment for this reason), the physician may consider dose reduction or switching medication.

4. Monitoring and Prevention of Hepatic Injury

(1) Baseline measurements of ALT, AST, and total bilirubin must be obtained within the first 3 months of treatment.

(2) Seek immediate medical attention for liver function testing if unexplained nausea, vomiting, right upper abdominal pain, fatigue, anorexia, jaundice, or dark urine occurs during treatment.

(3) Discontinue or interrupt treatment if transaminases >3× upper limit of normal and total bilirubin >2× upper limit of normal.

5. Recognition and Management of DRESS Syndrome

(1) Seek immediate medical care if fever, rash, lymphadenopathy, or facial swelling develops.

(2) Remain vigilant for fever or lymphadenopathy even in the absence of rash.

(3) Immediately discontinue cenobamate and do not restart if DRESS is suspected.

6. Precautions for QT Shortening

(1) Inform the physician of all concomitant medications, especially those that may shorten the QT interval (e.g., certain antiarrhythmics).

(2) Seek prompt medical evaluation with ECG if persistent palpitations or syncope occurs.

7. Monitoring for Suicide Risk

(1) Patients and caregivers should watch for sudden mood changes, worsening depression, anxiety, agitation, insomnia, aggressive behavior, or suicidal thoughts.

(2) Contact a physician immediately if any of these symptoms appear.

8. Reduced Efficacy of Oral Contraceptives

Women of childbearing potential should use additional non-hormonal contraceptive methods (e.g., condoms, intrauterine devices) and not rely solely on oral contraceptives.

9. Discontinuation Protocol

(1) Do not discontinue abruptly; taper gradually over at least 2 weeks to avoid inducing status epilepticus.

(2) However, rapid discontinuation may be performed if treatment cessation is required due to severe adverse reactions.