Diazepam Nasal Spray and Valdecoxib: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Diazepam Nasal Spray
Valdecoxib
No brand names on record
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
Increased plasma exposure to diazepam and increased sedative side effects of diazepam
Interaction Deep Dive
Concomitant administration of diazepam with valdecoxib has resulted in an increased plasma exposure of diazepam. Although this increase does not require dose adjustments, sedative effects of diazepam may be increased. Patients should be cautioned about this effect and should be advised against performing any tasks that require complete mental alertness1.
Why it happens (mechanism)
Inhibition of cytochrome P450 3A4-mediated diazepam metabolism
Literature reports
1 report — tap to read
a) Concomitant administration of diazepam 10 mg twice daily with 40 mg valdecoxib twice daily for 12 days resulted in a 28% increase in plasma exposure of diazepam and no change in valdecoxib exposure 1.
Common questions
Can I take Diazepam Nasal Spray and Valdecoxib together?
Increased plasma exposure to diazepam and increased sedative side effects of diazepam Always confirm with your pharmacist or prescriber before making any change.
How serious is the Diazepam Nasal Spray and Valdecoxib interaction?
It is rated minor. Usually limited clinical impact.
How quickly could this interaction happen?
The documented onset is "delayed". Effects tend to build up gradually over days to weeks.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
Questions for your pharmacist
- Does my dose of Diazepam Nasal Spray or Valdecoxib need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there anything you'd monitor while I'm on both?
References (1)
- Product Information: Bextra(R) tablets, valdecoxib tablets. G.D. Searle LLC, Division of Pfizer Inc, New York, NY, 2004.
Keep reading about Diazepam Nasal Spray
Keep reading about Valdecoxib
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