Felbamate

From Anvita Health Wiki

Contents 1 Introduction 2 Indications 3 Dosage 4 Monitor 5 Adverse-effects 6 Drug-interactions 7 Mechanism-of-action 8 More General Terms 9 Internet Database 10 References

Introduction

• Tradename: Felbatol.

Indications

• monotherapy & adjunctive therapy in patients > 14 years of age with partial & secondary generalized seizures
• adjunctive therapy in patients > 2 years of age with partial & generalized Lennox-Gastaut syndrome
• reserve drug for patients with severe symptoms NOT responsive to other, less toxic agents
• intractable seizures [4]

Dosage

• Start 400 mg PO TID, max 3.6 g/day
• Pediatrics: Start 15 mg/kg/day, max 45 mg/kg/day
• do NOT discontinue abruptly

• Tabs: 400 & 600 mg.
• Suspension: 600 mg/5 mL.

Monitor

• complete blood count ( CBC) baseline, weekly during therapy & for 4 weeks after discontinuation [6]
• liver function tests ( LFTs)baseline & weekly
  
• monitor with anticonvulsants

Adverse-effects

• common (> 10%)

• nausea, anxiety, headache, fatigue, dizziness, diarrhea, anorexia, vomiting, constipation, cough

• less common (1-10%)

• drowsiness, insomnia, blurred or double vision, clumbsiness, weight gain, depression, behavioral changes, clouded sensorium, lethargy, muscle twitches, slurred speech, uncontrollable eye movements, acne, skin rash

• uncommon (< 1%)

• alopecia, bleeding gums, gingival hyperplasia

• other

• aplastic anemia (marked increased incidence)
• hepatotoxicity
  
• drug adverse effects of anticonvulsants

Drug-interactions

• felbamate increases levels of phenytoin, valproic acid
• felbamate decreases carbamazepine level, but increases epoxide
• phenytoin & carbamazepine decrease felbamate levels

Mechanism-of-action

• potentiates GABA receptor-linked Cl- channels
• inhibits spontaneous discharges from voltage-dependent Na+ channels
• inhibits NMDA receptors
• inhibits AMPA receptors [5]

More General Terms

• anticonvulsant

Internet Database

PubChem: 3331

References

1. The Pharmacological Basis of Therapeutics, 9th ed. Gilman et al, eds. Permagon Press/McGraw Hill, 1996
2. Harrison's Principles of Internal Medicine, 13th ed. Companion Handbook. Isselbacher et al (eds), McGraw-Hill Inc. NY, 1995, pg 702
3. Kaiser Permanente Northern California Regional Drug Formulary, 1998
4. Department of Veterans Affairs, VA National Formulary
   - restricted to neurology
5. UpToDate 13.3 [1]
6. Prescriber's Letter 17(7): 2010 Recommended Lab Monitoring for Common Medications Liver Function Test Scheduling Detail-Document#: [2] (subscription needed) [3]

felbamate (Felbatol)