Ontozry (Cenobamate)

Cenobamate is used as an antiepileptic agent targeting seizure activity.

• Partial‑onset seizures: reduces seizure frequency and severity in patients with focal epilepsy.
• Epilepsy: provides adjunctive therapy for adults with uncontrolled focal seizures despite other treatments.
• Adjunctive seizure control: enhances overall seizure management when combined with other antiepileptic drugs.

• Cenobamate enhances the inactivation of voltage‑gated sodium channels, stabilizing neuronal membranes and reducing hyperexcitability. It also acts as a positive allosteric modulator of GABA_A receptors, increasing inhibitory neurotransmission and contributing to its anticonvulsant effect.

Cenobamate may cause a range of adverse reactions.

Common Side Effects

• Dizziness: sensation of light‑headedness or unsteadiness.
• Somnolence: excessive sleepiness or fatigue.
• Nausea: feeling of stomach upset or urge to vomit.
• Headache: mild to moderate head pain.
• Diplopia: double vision.
• Balance disorder: difficulty maintaining equilibrium.

Serious or Rare Side Effects

• Hyponatremia: low blood sodium levels requiring monitoring.
• Rash or Stevens‑Johnson syndrome: severe skin reactions.
• Suicidal ideation: thoughts of self‑harm.
• Severe respiratory depression: difficulty breathing.
• Hepatotoxicity: liver enzyme elevations.
• Cardiac arrhythmias: irregular heart rhythms.

Cenobamate requires careful monitoring and patient counseling.

• Baseline labs: obtain electrolytes and liver function tests before initiation.
• Dose titration: increase gradually to minimize adverse effects.
• Concomitant CNS depressants: monitor for enhanced sedation.
• Pregnancy: avoid use unless benefits outweigh potential risks.
• Renal/hepatic impairment: adjust dosing as clinically indicated.
• Store at room temperature: keep in original container, protect from moisture and direct sunlight.

Cenobamate interacts with several medications that may alter its efficacy or safety.

Major Interactions (Avoid)

• Strong CYP3A4 inhibitors (e.g., ketoconazole): may increase cenobamate levels.
• Carbamazepine, phenytoin, phenobarbital: may reduce cenobamate concentration.
• Other sodium channel blockers (e.g., lamotrigine): risk of additive toxicity.

Moderate Interactions (Monitor Closely)

• Moderate CYP3A4 inducers (e.g., rifampin): may lower cenobamate exposure.
• Antidepressants (e.g., fluoxetine): potential for increased CNS depression.
• Anticoagulants (e.g., warfarin): monitor INR for possible changes.