Acetaminophen And Codeine and Valerian: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jul 1, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Acetaminophen And Codeine
Valerian
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.
Your acetaminophen with codeine is a pain reliever that contains an opioid, and opioids can make you feel drowsy or slow your breathing. Valerian is an herbal supplement that people use to relax or sleep, and it works on the same calming brain chemistry.
When you take both together, those sleepy effects can add up. You might feel more drowsy, dizzy, or foggy than you expect. This concern comes mainly from lab and animal research, so it is not certain, but it is worth respecting. The good news is your care team can manage this easily. Just let your pharmacist or doctor know you use valerian, and avoid driving until you know how the combination affects you.
Effect: Additive CNS and respiratory depression when valerian is combined with codeine (an opioid analgesic co-formulated with acetaminophen).
Mechanism: Both agents enhance GABAergic tone; valerian modulates GABA neurotransmission and receptor function, layering onto opioid-mediated CNS depression. This is a pharmacodynamic (additive) interaction, not a metabolic one.
- Direction: Increased sedation/CNS depression.
- Onset: Unspecified.
- Evidence: Theoretical (animal/lab data).
- Management: Use with caution; counsel against operating heavy machinery or driving; monitor for excess sedation and respiratory depression. Dose may be individualized by the care team.
What happens
Additive central nervous system depression
Interaction Deep Dive
In animal research, valerian produced sedative effects through its influence on gamma aminobutyric acid neurotransmission. Combining it with opioid analgesics may lead to additive depression of both the CNS and respiration. Whenever valerian is taken together with an opiate, caution is warranted1.
Why it happens (mechanism)
Modulation of gamma aminobutyric acid neurotransmission and receptor function
How to manage this interaction
This combination can add to drowsiness, so a few simple steps keep you safe:
- Keep taking your prescribed medication unless your doctor tells you otherwise, and tell your pharmacist or prescriber that you use valerian.
- Avoid driving or operating heavy machinery until you know how the two affect you together.
- Watch for warning signs like unusual sleepiness, confusion, or slowed breathing, and get help if these occur.
Your care team may adjust timing or dosing and monitor you more closely. Because the evidence here is mostly theoretical, this is usually manageable with caution and good communication.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Acetaminophen And Codeine and Valerian together?
Combining valerian with acetaminophen-codeine may add to drowsiness and, in theory, slow breathing, so avoid driving until you know how you react and tell your pharmacist or doctor you use valerian. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Acetaminophen And Codeine and Valerian interaction?
It is rated moderate. Can be significant — usually manageable with monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How is the Acetaminophen And Codeine and Valerian interaction managed?
This combination can add to drowsiness, so a few simple steps keep you safe: Keep taking your prescribed medication unless your doctor tells you otherwise, and tell your pharmacist or prescriber that you use valerian. Avoid driving or operating heavy machinery until you know how the two affect you together. Watch for warning signs like unusual sleepiness, confusion, or slowed breathing, and get he… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Acetaminophen And Codeine or Valerian 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)
- Abebe W: Herbal medication: Potential for adverse interactions with analgesic drugs. J Clin Pharm Ther 2002; 27(6):391-401. PubMed
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