Valproate and Cimetidine Interaction
Drug interaction information between Valproate and Cimetidine.
Valproate and Cimetidine have a documented major interaction in FDA labeling.
FDA drug labeling documents a major-severity interaction between Valproate and Cimetidine. Major interactions are generally avoided, moderate ones may need monitoring or a dose adjustment, and minor ones are usually low-risk. This page shows the documented mechanism and guidance. Label-documented interactions are not a complete safety review, so always confirm your own medications with a pharmacist or doctor. Educational information, not medical advice.
How They Interact
Cimetidine does not interfere with how the body breaks down or clears valproate. This means the amount of valproate in your blood should remain stable.
What To Do
You can take these medications together without needing to change your dose. Your doctor will continue to monitor you as usual.
FDA Label Information
Cimetidine and Ranitidine Cimetidine and ranitidine do not affect the clearance of valproate.
Valproate Also Interacts With
- Ranitidine major
- Clarithromycin moderate
- Lidocaine Topical moderate
- Risperidone moderate
- Aspirin minor
Cimetidine Also Interacts With
- Levofloxacin major
- Posaconazole major
- Risperidone major
- Empagliflozin moderate
- Empagliflozin/Linagliptin moderate
Frequently Asked Questions
Can I take Valproate and Cimetidine together?
This is a major interaction. You can take these medications together without needing to change your dose. Your doctor will continue to monitor you as usual.
How serious is the interaction between Valproate and Cimetidine?
This interaction is classified as "major" severity by the FDA. Major interactions may be life-threatening or cause serious side effects.
Why do Valproate and Cimetidine interact?
Cimetidine does not interfere with how the body breaks down or clears valproate. This means the amount of valproate in your blood should remain stable.
Understanding the Valproate and Cimetidine Interaction
FDA-approved prescribing information for these two drugs flags their combination as a major-severity interaction. Valproate belongs to the Anticonvulsant / Mood Stabilizer class and Cimetidine belongs to the H2 Receptor Antagonist class - two categories that can collide when co-prescribed. The mechanism described in FDA labeling is: Cimetidine does not interfere with how the body breaks down or clears valproate. Severity tiers matter: major flags generally advise avoidance, moderate flags often require monitoring or dose adjustment, and minor flags may only call for awareness.
Context around a specific patient determines real-world impact. Valproate has 41 total documented interactions on file in this dataset, and Cimetidine has 77. Each additional medication compounds the interaction surface, which is why pharmacists run full-profile checks rather than evaluating one pair at a time. FDA-derived guidance for this pair is: You can take these medications together without needing to change your dose. Timing of doses, renal and hepatic function, age, and other concurrent prescriptions all shape whether a labeled interaction matters clinically.
An interaction flag is not a verdict. A large share of labeled interactions are managed routinely in clinical practice, the fix may be as simple as spacing doses or adding a monitoring test. Others require the prescriber to choose a different medication entirely. This page surfaces FDA-sourced labeling and openFDA data for educational purposes only; it is not medical advice and cannot account for your full clinical picture. Never start, stop, or adjust either Valproate or Cimetidine based on a web page, speak with your prescriber or pharmacist before making any change.
Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. Always consult your healthcare provider about drug interactions.
Read our methodology - how this data is sourced, computed, and verified.