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# Lennox-Gastaut Syndrome (LGS)
## Overview
LGS is a severe form of childhood-onset epilepsy characterized by multiple seizure types (typically tonic, atonic, and atypical absence), characteristic slow spike-and-wave EEG patterns, and cognitive impairment. Management usually requires polypharmacy.
## Primary Indications
Adjunctive therapy for seizures associated with LGS. Primary agents include **Clobazam, Rufinamide, Topiramate, Felbamate, Cannabidiol, and Lamotrigine**.
## Adult Dosing
* **Clobazam:** Start 5 mg/day; titrate to 20 mg/day (max 40 mg/day).
* **Rufinamide:** Start 400–800 mg/day; titrate to 3,200 mg/day (max 3,200 mg/day).
* **Cannabidiol:** 10 mg/kg/day; titrate to 20 mg/kg/day.
* **Felbamate:** Start 1,200 mg/day; titrate to 3,600 mg/day.
## Pediatric Dosing
* **Clobazam (≥2 years):** Weight-based: <30 kg, start 5 mg/day (max 20 mg/day); ≥30 kg, start 10 mg/day (max 40 mg/day).
* **Rufinamide (≥1 year):** Start 10 mg/kg/day; titrate up to 45 mg/kg/day (max 3,200 mg/day).
* **Cannabidiol (≥1 year):** 2.5 mg/kg BID; titrate to 10 mg/kg BID (max 20 mg/kg/day).
* **Topiramate (≥2 years):** Start 1–3 mg/kg/day; titrate to 5–9 mg/kg/day (max 400 mg/day).
## Dose Adjustments
* **Hepatic Impairment:** Reduce starting and maintenance doses for Clobazam; Felbamate requires extreme caution (monitor LFTs).
* **Renal Impairment:** Topiramate/Rufinamide may require dose reductions or slower titration in severe impairment.
## Contraindications
* **Felbamate:** History of hepatic impairment or blood dyscrasias.
* **Rufinamide:** Familial Short QT Syndrome.
* **General:** Known hypersensitivity to any agent.
## Adverse Effects
* **Common:** Somnolence, fatigue, irritability, decreased appetite, GI distress (diarrhea/nausea).
* **Serious:** Stevens-Johnson Syndrome (Lamotrigine, Rufinamide, Topiramate), Aplastic Anemia/Hepatic Failure (Felbamate), Suicidal Ideation.
## Key Drug Interactions
* **CYP450:** Clobazam and Cannabidiol may inhibit/induce other AEDs.
* **CNS Depressants:** Avoid concurrent use of other benzodiazepines or alcohol to minimize respiratory depression.
* **Valproate:** Increases serum concentrations of Rufinamide; requires dose reduction.
## Monitoring
* **Safety:** CBC and LFTs (baseline and periodic for Felbamate, Valproate, and Felbamate).
* **Efficacy:** Seizure frequency logs.
* **Cardiac:** EKG for patients on Rufinamide if history of arrhythmias exists.
* **Mental Health:** Monitor for worsening depression or suicidal behavior.
## Clinical Pearls
* **Tapering:** Never discontinue AEDs abruptly due to risk of status epilepticus withdrawal.
* **Protocol Variance:** Titration schedules vary by institutional protocol; aggressive initial dosing increases side effect burden (e.g., somnolence with Clobazam).
* **Cannabidiol:** Ensure use of FDA-approved product (Epidiolex) to avoid variable potency and contaminants in OTC supplements.
* **Felbamate:** Reserved as third-line due to black box warnings; requires signed patient consent.
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**Educational Disclaimer:** This summary is for informational purposes for healthcare professionals. Clinical practice guidelines and prescribing information (package inserts) are subject to change. Always verify dosing and contraindications via the most current product labeling and institutional pharmacy guidelines before prescribing.
