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Does Phenobarbital Interact with Valproate Sodium?

CDI records a major classification for Phenobarbital and Valproate Sodium. The stored summary is: Sodium valproate increases phenobarbital serum levels. Phenobarbital blood levels should be closely monitored and dosage adjustments made as clinically indicated. The mechanism involves increased phenobarbital serum levels. Patients taking both medications should consult their healthcare provider before starting, stopping, or changing the dosage of either drug. This record was extracted from drug labeling through openFDA. NIH/NLM RxNorm is used for drug identities. The summary and severity classification are CDI's processed information, not a verbatim source quotation. Product, route, and patient circumstances matter.

Severity: Major
Management: Close medical supervision required
Data Source: U.S. FDA via OpenFDA

Recorded Mechanism

Increased phenobarbital serum levels

What To Tell Your Doctor or Pharmacist

If you are taking Phenobarbital and your doctor is considering prescribing Valproate Sodium (or vice versa), make sure to:

Inform your doctor and pharmacist of all current medications, including over-the-counter drugs and supplements
Ask whether the benefits of combining these medications outweigh the risks for your specific situation
Ask what symptoms to watch for that would indicate the interaction is causing problems
Ask how frequently you should be monitored while these are co-prescribed
Ask whether any dosage adjustments are needed
Never stop or change either medication without first consulting your healthcare provider

💊 Phenobarbital(Donnatal)+💊 Valproate Sodium(Valproate Sodium)

Severity & Interaction Details

⚠️

major

Use with caution — major interaction

Serious risk of clinically significant harm. Generally avoid; if used, monitor closely.

Severity scale

MinorContra

On record

Yes

Drug A class

—

Drug B class

—

Source

NLP:phenobarbital

What this means in plain English

Sodium valproate increases phenobarbital serum levels. Phenobarbital blood levels should be closely monitored and dosage adjustments made as clinically indicated.

About Phenobarbital and Valproate Sodium

Phenobarbital is also sold under the brand name Donnatal. Valproate Sodium additionally carries an FDA boxed warning, the FDA's strongest safety alert.

Source and Limitations

This record was produced by automated extraction from drug-label information, including AI processing. The summary and mechanism are not verbatim FDA quotations. The drug profiles below may describe different formulations from the source label. Confirm the exact product and route with your pharmacist. This page does not establish independent clinical review.

📖 Source: NLP:phenobarbital

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How this information is prepared: CDI uses automated extraction, including AI, to summarize drug labeling from openFDA and includes separately identified curated-reference records. RxNorm helps identify medications; it does not verify interaction claims. Extracted summaries and CDI severity classifications can contain errors and are not verbatim FDA statements or independent clinical review. Maintained by CheckDrugInteractions.com. See our methodology or report a correction at support@checkdruginteractions.com.

Data sourced from U.S. FDA drug labeling via openFDA and the NIH National Library of Medicine, supplemented with a small number of well-established interactions from curated clinical references. For informational purposes only. Always consult your pharmacist or physician.