In neonatal rats, CBD at moderate to high doses significantly enhanced the antiseizure effects of a sub-effective dose of phenobarbital, suggesting potential as an adjunct therapy for newborn seizures.
Neonatologists treating seizures, pediatric neurologists, epilepsy pharmacology researchers
CBD enhanced sub-effective phenobarbital doses to achieve significant seizure control
What the researchers found
Low CBD doses (3 and 30 mg/kg) had limited antiseizure effects alone, while higher doses (100 and 200 mg/kg) modestly reduced seizures. However, CBD at 30, 100, or 200 mg/kg significantly enhanced the efficacy of a sub-effective dose of phenobarbital (10 mg/kg), demonstrating dose-dependent potentiation. This synergistic effect could allow lower phenobarbital doses, reducing side effects.
Why it matters
Neonatal seizures are common and difficult to treat, with many newborns showing resistance to phenobarbital, the first-line treatment. CBD's ability to enhance phenobarbital's effects could allow effective seizure control at lower drug doses, potentially reducing the neurotoxic side effects associated with high-dose phenobarbital in developing brains.
The numbers in context
CBD doses: 3, 30, 100, 200 mg/kg. PB doses: 3, 10, 30, 50, 75 mg/kg. PTZ: 100 mg/kg. CBD 30-200 mg/kg + PB 10 mg/kg: significant seizure reduction. CBD alone: modest effects only at 100-200 mg/kg. PB 10 mg/kg alone: sub-effective. P10 Wistar rats.
How the study worked
Neonatal seizure model using 10-day-old Wistar rats. Rats were pretreated with phenobarbital (3-75 mg/kg) and/or CBD (3-200 mg/kg), then seizures were induced with subcutaneous PTZ (100 mg/kg). Seizure latency, duration, and severity were assessed.
What this study cannot tell us
Animal model in 10-day-old rats, which may not directly translate to human neonatal seizures. Single seizure induction method (PTZ). Acute dosing only. High CBD doses used may not be achievable in neonates. No pharmacokinetic data on CBD-PB interaction in neonates.
How to read the evidence
Preliminary evidence from an animal model using acute dosing in neonatal rats.
When this study was published
2025 preclinical study examining CBD-phenobarbital interaction in a neonatal seizure model.
The bigger picture
The combination of CBD with existing antiseizure medications is an active area of clinical interest. This preclinical study provides a rationale for testing CBD as an adjunct to phenobarbital specifically in neonatal seizures, where treatment options are limited and the developing brain is particularly vulnerable to medication side effects.
Questions still open
- What is the mechanism of CBD-phenobarbital synergy? Would this potentiation occur in human neonates? Could CBD allow significant phenobarbital dose reductions in clinical practice? What are the safety implications of CBD-PB combination in developing brains?
Common questions
Can CBD be combined with phenobarbital for seizures?
Why is this important for newborns?
Read the original research
Cannabidiol potentiates phenobarbital effects in the control of pentylenetetrazole (PTZ)-induced epileptic seizures in neonate rats.
Frontiers in pediatrics, 13, 1673345
Citation
Pinto, Lillian Soares; de Oliveira, Matheus Silva; Borges, Giovanna Bruno; de Castro, Olagide Wagner; Moreira, Fabrício de Araújo; Santos, Victor Rodrigues. (2025). Cannabidiol potentiates phenobarbital effects in the control of pentylenetetrazole (PTZ)-induced epileptic seizures in neonate rats.. Frontiers in pediatrics, 13, 1673345. https://doi.org/10.3389/fped.2025.1673345
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