Ethosuximide

From Anvita Health Wiki

Contents 1 Introduction 2 Indications 3 Dosage 4 Monitor 5 Adverse-effects 6 Drug-interactions 7 Test-interactions 8 Laboratory 9 More General Terms 10 Internet Database 11 References

Introduction

• Tradename: Zarontin.

Indications

• absence ( petit mal) seizures
• akinetic epilepsy

Dosage

• 250 mg PO QD if 3-6 years of age
• 500 mg PO QD > 6 years

• Tabs: 250 mg.
• Elixir: 250 mg/5 mL.

Monitor

• liver function tests periodically [6]
  
• monitor with anticonvulsants

Adverse-effects

• common (> 10%)

• Stevens-Johnson syndrome, lupus-like syndrome, anorexia, ataxia, dizziness, drowsiness, hiccups, headache, nausea/vomiting, weight loss

• less common (1-10%)

• aggressiveness, depression, nightmares, weakness, fatigue

• uncommon (< 1%)

• agranulocytosis, leukopenia, aplastic anemia, thrombocytopenia, pancytopenia, paranoid psychosis, urticaria, exfoliative dermatitis

• other: ataxia
  

• drug adverse effects of anticonvulsants

Drug-interactions

• agents which may increase ethosuximide metabolism

• carbamazepine
• phenytoin
• primidone
• phenobarbital

• valproic acid may increase or decrease ethosuximide levels
• ethosuximide induces cyt P450 3A4

• may diminish levels of drugs metabolized by cyt P450 3A4

• isoniazid may inhibit hepatic metabolism of ethosuximide

Test-interactions

• may cause positive direct Coomb's test
• may increase ANA titer
• may increase serum AST

Laboratory

• specimen:

• serum, plasma ( heparin, EDTA)
• collect at trough concentration
• stable for several hours at room temperature
• stable for 1 year at -20 degrees C

• methods: HPLC, GLC, EIA, FPIA

More General Terms

• succinimide
• anticonvulsant

Internet Database

PubChem: 3291
PubChem: 551129

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 701
3. Kaiser Permanente Northern California Regional Drug Formulary, 1998
4. Clinical Guide to Laboratory Tests, 3rd ed. Teitz ed., W.B. Saunders, 1995
5. Medical Knowledge Self Assessment Program (MKSAP) 15, American College of Physicians, Philadelphia 2009
6. Prescriber's Letter 17(7): 2010 Recommended Lab Monitoring for Common Medications Liver Function Test Scheduling Detail-Document#: [1] (subscription needed) [2]

ethosuximide (Zarontin)