- An ‘older’ but effective anticonvulsant. It is most used in primary generalised epilepsies, particularly CAE.
- There is now class 1 evidence for efficacy in CAE and it is regarded as the drug of choice. 
NOTABLE Side Effects:
- The main side effect is GI symptoms (abdominal pain). This generally is dose-dependent but can be intolerable and necessitate stopping the drug.
- Joint pain
- Drowsiness or lethargy
- All anticonvulsants are potentially teratogenic and this is often dose related (see section: Pregnancy and AEDs)
- For a complete list of adverse effects, appropriate formularies should be consulted.
- The initiation and escalation dose depends upon age, weight, syndrome, seizure frequency and severity, and side effect profile.
- Unfortunately, one dose regime does not fit all. A Paediatric Neurologist should be consulted if there is uncertainty.
A commonly used regime is below:
- 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 in children of weight approximately up to 30-40kgs. Consult appropriate formularies for higher weights and in the adult range.
- These dosages are only a guideline and appropriate formularies should be consulted as needed.
- 250mg capsule or 50mg/ml syrup forms.
Monitoring and Levels:
- No routine blood tests are necessary.
- No significant drug interactions occur.
This website was created in March 2012. This page was last modified in December 2017.
 Tracy A. Glauser et al.Ethosuximide, Valproic Acid, and Lamotrigine in Childhood Absence Epilepsy. N Engl J Med 2010; 362:790-799