What are the indications for starting anti-epileptic (AED) medication after a first seizure?

Indications for Starting Antiepileptic Drugs After First Seizure

Antiepileptic drugs (AEDs) should not be initiated after a first unprovoked seizure without evidence of brain disease or injury, as they do not alter long-term seizure outcomes despite reducing short-term recurrence risk. 1

Decision Algorithm for AED Initiation

First Unprovoked Seizure

1. Do NOT initiate AEDs if:

   • Patient has returned to baseline clinical status
   • No evidence of brain disease or injury
   • First unprovoked seizure without structural abnormalities 1

2. Consider initiating AEDs if:

   • Remote history of brain disease or injury (stroke, trauma, tumor, other CNS disease)
   • Abnormal EEG findings
   • Structural lesions discovered on imaging 1

3. Provoked Seizures:

   • Do NOT initiate AEDs for provoked seizures
   • Instead, identify and treat the precipitating medical condition 1

Risk Assessment

The decision to start AEDs should be informed by recurrence risk assessment:

• Low risk: Single unprovoked seizure without risk factors (~35% recurrence at 2 years)
• Medium risk: Single unprovoked seizure with some risk factors
• High risk: Remote symptomatic seizure with structural abnormalities (~75% recurrence at 5 years) 2

Evidence Analysis

The American College of Emergency Physicians guideline (2014) provides clear recommendations against initiating AEDs in the ED for patients with first unprovoked seizures without evidence of brain disease or injury 1. This recommendation is supported by evidence showing that while immediate treatment reduces short-term seizure recurrence (RR 0.49 at one year), it does not affect long-term remission rates 3.

For patients with a first seizure and remote history of brain disease/injury, emergency physicians may initiate AEDs or defer in coordination with other providers 1. The Number Needed to Treat (NNT) to prevent a single additional seizure in the first year is approximately 5 for these patients 1.

Important Considerations

• Risk-benefit assessment: Treatment reduces recurrence risk by about 50% in the short term but exposes patients to medication side effects 3
• Medication adverse effects: AEDs are associated with significant adverse events (RR 1.49 compared to deferred treatment) 3
• Long-term outcomes: No difference in five-year remission rates between immediate and delayed treatment 3

Discharge and Follow-up

For patients not started on AEDs after a first seizure:

• Ensure return to baseline mental status
• Verify normal or non-acute findings on neuroimaging (if performed)
• Arrange reliable follow-up with neurology
• Provide seizure precautions and safety measures
• Advise on driving restrictions according to local laws 4

Common Pitfalls

1. Overtreatment: Initiating AEDs for all first seizures despite evidence showing no long-term benefit for unprovoked seizures without risk factors
2. Undertreatment: Failing to initiate AEDs for patients with high recurrence risk (remote symptomatic seizures)
3. Inadequate follow-up: Not arranging appropriate neurological evaluation including EEG to identify epilepsy syndromes and predict recurrence risk
4. Missing treatable causes: Failing to identify and treat underlying causes of provoked seizures

Remember that while immediate treatment reduces short-term recurrence risk, it does not alter the long-term prognosis for seizure freedom and exposes patients to potential medication side effects. The decision should be based on individual risk factors, with particular attention to evidence of brain disease or injury that significantly increases recurrence risk.