Antiseizure medication (ASM) withdrawal in seizure-free patients

Here’s a very detailed summary of the practice advisory update on antiseizure medication (ASM) withdrawal in seizure-free patients:

Objective and Methods

• Update the 1996 American Academy of Neurology practice parameter
• Systematic review of literature published from January 1991 to March 2020

Key Findings

Adults

• Long-term (24-60 months) risk of seizure recurrence:
  • Possibly higher among those who taper ASMs vs. those who don’t
  • 15% vs. 7% recurrence rate (Class I study)
  • Hazard ratio for recurrence: 2.9 (95% CI 1.8-4.6) in one Class III study

Children

• No significant difference in seizure recurrence between:
  • Tapering ASMs after 2 years vs. 4 years of seizure freedom
  • Tapering at 18 months vs. 24 months (insufficient evidence)

Risk Factors for Seizure Recurrence

• Adults:
  • Shorter seizure-free period (2 years vs. longer)
  • Abnormal psychiatric examination
  • Specific ASMs (valproate, phenobarbitone, primidone, phenytoin)
• Children:
  • Epileptiform activity on EEG possibly increases risk

Status Epilepticus

• ASM withdrawal possibly does not increase risk in adults

Quality of Life

• ASM weaning possibly does not change quality of life in seizure-free adults

Mortality

• Insufficient evidence to support or refute changes in mortality risk

Speed of ASM Withdrawal (Children)

• No significant difference in recurrence risk between:
  • 25% reduction every 10 days to 2 weeks
  • 25% reduction every 2 months

Recommendations

1. Clinicians should inform adults who have been seizure-free for 24 months or more that:
   • There is a possibility of increased seizure recurrence risk with ASM withdrawal
   • Recurrence risk is likely low overall but may double compared to those who continue ASMs
   • There is uncertainty about the exact risk increase
2. Clinicians should advise children who have been seizure-free for at least 2 years that:
   • There is probably no additional risk reduction by waiting 4 years vs. 2 years to withdraw ASMs
3. Clinicians should counsel children and caregivers that:
   • An epileptiform EEG abnormality may be associated with increased seizure recurrence risk
4. Clinicians may advise patients that:
   • ASM withdrawal possibly does not increase the risk of status epilepticus (adults)
   • ASM withdrawal possibly does not change quality of life (adults)
5. When withdrawing ASMs in children, clinicians may consider:
   • Using a withdrawal rate of 25% reduction every 10 days to 2 weeks
   • Or using a withdrawal rate of 25% reduction every 2 months

Limitations and Considerations

• Limited high-quality evidence for many aspects of ASM withdrawal
• Individualized decision-making is crucial, considering patient preferences and risk factors
• Further research needed on specific electroclinical syndromes and post-epilepsy surgery patients
• EEG type and duration for assessing recurrence risk not specified in studies

This summary provides a comprehensive overview of the key points from the practice advisory update on ASM withdrawal in seizure-free patients.

Source: Gloss et al. 2021