Ethosuximide | Epilepsy clinician handbook
Ethosuximide is an ‘older’, though 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 Class 1 evidence for efficacy in CAE and it is regarded as the drug of choice.
Important: Dosing information
Initiation and escalation doses on this webpage are a guide only.
All medications must be individualised based on:
- patient age, weight, co-morbidities
- disease, seizure type, frequency, duration
- medication metabolism, interactions, side-effect profile characteristics.
Further consultation with appropriate formularies or a paediatric neurologist may be required.
Dosing
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.
Formulary
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 anti-seizure medications are potentially teratogenic and this is often dose related.
- For a complete list of adverse effects, appropriate formularies should be consulted.
Interactions and precautions
No significant drug interactions occur. No routine blood tests are necessary.
Resources
This information is reviewed annually by the Sydney Children’s Hospitals Network Paediatric Epilepsy NSW working group which includes medical, nursing, and pharmacy representation.