Phenobarbital and Valproate: Drug Interaction Guide
Quick answer: This combination requires caution. Phenobarbital and Valproate can be used together with adjustments and monitoring.
How Phenobarbital interacts with Valproate
Sodium valproate inhibits hepatic microsomal enzymes that metabolize phenobarbital, increasing phenobarbital concentrations by 30-50% and the risk of sedation and respiratory depression.
What you should do
Reduce phenobarbital dose by 30-50% when adding valproate and monitor for sedation; check phenobarbital levels at steady state.
Key facts
Severity
Moderate — caution required
Mechanism
Sodium valproate inhibits hepatic microsomal enzymes that metabolize phenobarbital, increasing phenobarbital concentrati...
Action
Reduce phenobarbital dose by 30-50% when adding valproate and monitor for sedation; check phenobarbital levels at steady...
Frequently asked questions
Can I take Phenobarbital and Valproate together?
With caution. Reduce phenobarbital dose by 30-50% when adding valproate and monitor for sedation; check phenobarbital levels at steady state.
What is the severity of this interaction?
The interaction between Phenobarbital and Valproate is classified as Moderate — caution required. Sodium valproate inhibits hepatic microsomal enzymes that metabolize phenobarbital, increasing phenobarbital concentrations by 30-50% and the risk of sedation and respiratory depression.
What should I do if I'm prescribed both?
Reduce phenobarbital dose by 30-50% when adding valproate and monitor for sedation; check phenobarbital levels at steady state. Always consult your prescribing clinician — do not stop or change medications without medical guidance.
Last reviewed: by iMedic Medical Editorial Team. Our editorial process.