Which anticonvulsant medications are appropriate for infants aged 0–12 months?

Anticonvulsants for Infants (0-12 months)

Phenobarbital is the first-line anticonvulsant for infants with seizures, regardless of etiology (HIE, stroke, hemorrhage), with an 80% seizure control rate compared to only 28% for levetiracetam. 1

First-Line Treatment Algorithm

Standard Approach (Most Etiologies)

• Phenobarbital 20 mg/kg IV is the definitive first-line agent 1
  • If seizures persist after 15 minutes: give additional 20 mg/kg
  • Achieves seizure control in 80% of neonates 1
  • Moderate-quality evidence shows phenobarbital is significantly more effective than levetiracetam (RR = 0.35,95% CI 0.22-0.56) 1

Exception: Suspected Channelopathy

• If positive family history suggests channelopathy (KCNQ2/KCNQ3 variants):
  • Use phenytoin or carbamazepine (sodium channel blockers) as first-line 1
  • 91% expert consensus supports this approach 1

Critical Caveat: Without a positive family history, do NOT delay treatment by trying sodium channel blockers first—use phenobarbital immediately to avoid treatment delays 1.

Second-Line Treatment Algorithm

When first-line therapy fails:

For Most Etiologies (HIE, stroke, hemorrhage):

• Phenytoin OR levetiracetam 1
• Alternative options: midazolam or lidocaine (less favorable) 1

For Suspected Channelopathy:

• Phenytoin or carbamazepine (sodium channel blockers) 1
• Choice depends on clinical state (critically ill vs. stable) and regional drug availability

For Cardiac Disorders:

• Levetiracetam preferred to avoid cardiac effects of phenytoin 1

For Refractory Seizures Without Identified Etiology:

• Trial of pyridoxine (add-on to ASM) if vitamin B6-dependent epilepsy suspected 1
• If pyridoxine fails, consider pyridoxal 5'-phosphate (PLP) 1

Duration of Treatment

Discontinue anticonvulsants BEFORE hospital discharge once acute provoked seizures cease, regardless of MRI or EEG findings 1. This applies when there is no evidence of neonatal-onset epilepsy.

• 87% expert consensus supports early discontinuation 1
• Maintenance therapy shows no benefit for mortality, neurodevelopmental outcomes, or epilepsy risk (low-certainty evidence) 2
• Phenobarbital should be used for the shortest duration possible due to potential adverse effects 1

Safety Considerations

Hypotension risk: Phenobarbital causes hypotension in 17% vs. 5% with levetiracetam 1. However, this does not outweigh phenobarbital's superior efficacy.

Common pitfall: Despite levetiracetam's better safety profile, it fails more frequently due to lack of effectiveness (40% failure rate vs. 22% for valproate in older children) 3. The 2023 ILAE guidelines clearly demonstrate phenobarbital's superior efficacy in neonates 1.

Evidence Quality Note

The 2023 ILAE Task Force guidelines 1 represent the most authoritative and recent evidence, based on moderate-quality RCT data showing phenobarbital's clear superiority over levetiracetam for neonatal seizures. While one 2022 study 4 suggested levetiracetam effectiveness in asphyxiated infants, the larger, higher-quality ILAE guideline evidence takes precedence.