CBD Enhanced the Seizure-Fighting Effects of Phenobarbital in Newborn Rats

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.

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.

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 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.

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.