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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 EEG slow spike-wave patterns, and cognitive impairment. Management frequently requires polytherapy.
## Primary Indications
Adjunctive treatment for seizures associated with LGS in patients typically aged 1 year and older.
## Adult Dosing
* **Rufinamide:** Start 400–800 mg/day in two divided doses; titrate by 400–800 mg every 2 days to max 3200 mg/day.
* **Clobazam:** Start 5–10 mg/day; titrate to 20 mg/day based on weight and response.
* **Cannabidiol (CBD):** Start 2.5 mg/kg BID (5 mg/kg/day); after 1 week, increase to 5 mg/kg BID (10 mg/kg/day). Max 20 mg/kg/day.
## Pediatric Dosing
* **Rufinamide (≥1 year):** Start 10 mg/kg/day in two divided doses; increase by 10 mg/kg increments every other day to max 45 mg/kg/day (not to exceed 3200 mg/day).
* **Clobazam (≥2 years):** Weight <30 kg: Start 5 mg/day, increase to 10 mg/day; Weight ≥30 kg: Start 10 mg/day, increase to 20 mg/day.
* **Cannabidiol (≥1 year):** Start 2.5 mg/kg BID. Target 5 mg/kg BID (10 mg/kg/day). May increase to 10 mg/kg BID (20 mg/kg/day) based on tolerance.
## Dose Adjustments
* **Hepatic Impairment:** Clobazam and CBD require slower titration and significant dose reductions in moderate to severe hepatic impairment (Child-Pugh Class B/C).
* **Renal Impairment:** Rufinamide caution in severe impairment; no specific titration guidance provided by label.
## Contraindications
* **Rufinamide:** Familial Short QT Syndrome.
* **Cannabidiol:** Hypersensitivity to cannabinoids.
* **Clobazam:** Known hypersensitivity to benzodiazepines.
## Adverse Effects
* **Common:** Somnolence, fatigue, dizziness, ataxia, insomnia, aggression, and appetite suppression.
* **Serious:** Suicidal ideation/behavior, drug-induced liver injury (specifically CBD and valproate/clobazam combinations), and severe cutaneous adverse reactions (SCARs/DRESS, particularly with lamotrigine or rufinamide).
## Key Drug Interactions
* **Valproate:** Significantly increases serum concentrations of clobazam's active metabolite (N-desmethylclobazam); dose reduction of clobazam is often necessary.
* **CYP450 Inducers (e.g., Carbamazepine, Phenytoin, Phenobarbital):** Can decrease concentrations of rufinamide and clobazam.
* **CNS Depressants:** Additive sedation with other benzodiazepines, opioids, or alcohol.
## Monitoring
* **Liver Function Tests:** Baseline and periodically (especially for CBD or if combined with valproate).
* **Neurologic/Psychiatric:** Monitor for emergence or worsening of depression, suicidal thoughts, or unusual behavioral changes.
* **ECG:** Frequency monitoring recommended for rufinamide, especially if QT-prolonging agents are co-administered.
* **Therapeutic Response:** Seizure frequency logs.
## Clinical Pearls
* **Polytherapy is standard:** It is rare for LGS to be controlled by a single ASM; titration should be slow to minimize adverse effects.
* **Cannabidiol Safety:** When using CBD with valproate, monitor LFTs closely, as the combination carries a high risk of elevated transaminases.
* **Rapid Discontinuation:** Avoid abrupt withdrawal of any anticonvulsant to prevent status epilepticus.
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*Disclaimer: This information is for educational purposes and does not substitute for professional medical judgment. Always consult the latest FDA-approved package inserts, clinical guidelines, and institutional protocols before prescribing or administering medications.*
