Ethosuximide

Usage

  • An ‘older’ but effective anticonvulsant used for the treatment of absence seizures and sometimes absence status epilepticus.
  • It is most used in primary generalised epilepsies, particularly childhood absence epilepsy.
  • There is now class 1 evidence for efficacy in CAE and it is regarded as the drug of choice.1

Resources

  • 1Tracy A. Glauser et al.Ethosuximide, Valproic Acid, and Lamotrigine in Childhood Absence Epilepsy. N Engl J Med 2010; 362:790-799

Side effects

Possible side effects:

The main side effect is GI symptoms (abdominal pain). This is generally dose-dependent but can be intolerable and necessitate stopping the drug.

  • Hiccups
  • Rash
  • Joint pain
  • Drowsiness or lethargy
  • All anticonvulsants are potentially teratogenic and this is often dose related (see section: AED Prescribing - Pregnancy)

For a complete list of adverse effects, appropriate formularies should be consulted.

Dosing

  • The below initiation and escalation doses are only a guide and need to be individualised based on patient (age, weight, co-morbidities), disease (seizure type, frequency, duration) and medication (metabolism, interactions, side-effect profile) characteristics.

 

  • Situations that require more careful consideration include children with higher weights, polytherapy, or multiple co-morbidities. Consultation with appropriate formularies or a paediatric neurologist may be required in specific circumstances.

Commonly used regime

  • Start 10-15mg/kg/day in two divided doses increasing weekly.
  • Around 20mg/kg/day is a reasonable target dose. Higher doses above 30mg/kg/day may be effective but GI symptoms are more frequent.
  • Dosages per kilogram can only be used up to weights of 30-40kgs.
  • Maximum dosage in the older adolescent/adult range: 1500mg daily.

Preparations

  • 250mg capsule or 50mg/ml syrup forms.

Monitoring

No routine blood tests are necessary.

Interactions | Precautions

  •  No significant drug interactions occur.

 

Information last reviewed: 3/05/2023.