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# Lennox-Gastaut Syndrome (LGS)
## Overview
LGS is a severe form of childhood-onset epilepsy characterized by multiple seizure types, intellectual disability, and a specific slow spike-wave pattern on EEG. Management is often multi-drug therapy due to refractory nature.
## Primary Indications
Adjunctive treatment of seizures associated with LGS in patients ≥1 year of age.
## Adult Dosing
* **Rufinamide:** Start 400–800 mg/day in two divided doses. Increase by 400–800 mg every 2 days to max 3200 mg/day.
* **Clobazam:** Start 5 mg/day; titrate to 20 mg/day based on weight/tolerance.
* **Cannabidiol (Epidiolex):** Start 2.5 mg/kg twice daily (5 mg/kg/day); increase to 5 mg/kg twice daily (10 mg/kg/day) after 1 week. Max 20 mg/kg/day.
* **Topiramate:** Start 25 mg/day; titrate weekly by 25–50 mg increments to 200–400 mg/day in two divided doses.
* **Felbamate:** Start 1200 mg/day in 3–4 divided doses; increase by 600 mg every week to 3600 mg/day max.
## Pediatric Dosing
* **Cannabidiol (≥1 year):** 5 mg/kg/day initially, titrated to 10 mg/kg/day. May increase to 20 mg/kg/day based on response/tolerability.
* **Rufinamide (≥1 year):** 10 mg/kg/day in two doses; increase by 10 mg/kg every 2 days to max 45 mg/kg/day (not to exceed 3200 mg/day).
* **Clobazam (≥2 years):** Weight <30 kg: Start 5 mg/day, max 20 mg/day. Weight ≥30 kg: Start 10 mg/day, max 40 mg/day.
* **Topiramate (≥2 years):** Usual range 5–9 mg/kg/day in two divided doses.
## Dose Adjustments
* **Renal:** Rufinamide and Topiramate require reduction in severe renal impairment (CrCl <30 mL/min).
* **Hepatic:** Cannabidiol and Clobazam require caution/reductions in Child-Pugh B or C; monitor liver enzymes closely.
## Contraindications
* **Rufinamide:** Familial Short QT syndrome.
* **Felbamate:** History of hepatic impairment or bone marrow depression (due to aplastic anemia risk).
* **General:** Hypersensitivity to active ingredients or excipients.
## Adverse Effects
* **Systemic:** Somnolence, fatigue, dizziness, irritability.
* **Cannabidiol:** Elevated transaminases (ALT/AST), diarrhea, decreased appetite.
* **Rufinamide:** Shortened QT interval.
* **Felbamate:** Aplastic anemia, hepatotoxicity (routine monitoring required).
* **Topiramate:** Nephrolithiasis, metabolic acidosis, cognitive slowing.
## Key Drug Interactions
* **Valproate:** Significantly increases blood levels of Rufinamide and Clobazam (N-desmethylclobazam). Require dose reductions of co-administered drugs.
* **Enzyme Inducers (e.g., Carbamazepine, Phenytoin):** Reduce plasma concentrations of many anticonvulsants (especially Clobazam and Rufinamide).
* **CNS Depressants:** Additive sedation with alcohol or benzodiazepines.
## Monitoring
* **Labs:** LFTs (specifically with Cannabidiol and Felbamate), CBC (Felbamate), and serum bicarbonate (Topiramate).
* **Cardiac:** Baseline/follow-up EKG if on Rufinamide or risk of QT prolongation.
* **Mental Health:** Monitor for worsening depression or suicidal ideation (class-wide risk).
## Clinical Pearls
* **Precision:** These dosage ranges are standard references; individual protocols vary based on institutional guidelines and patient comorbidities.
* **Tapering:** Never abruptly discontinue anticonvulsants due to the risk of status epilepticus.
* **Education:** Caregivers must be educated on LGS seizure types, as some meds may exacerbate specific seizure morphologies (e.g., carbamazepine can worsen absence/myoclonic seizures in LGS).
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**Educational Disclaimer:** This information is for educational purposes only. Always verify current prescribing information, institutional protocols, and specific patient safety data in the package insert or therapeutic databases (e.g., Lexicomp, UpToDate) before prescribing.
