Drug & supplement interaction

Cnidium + Acetaminophen, Codeine, Doxylamine

Acetaminophen, Codeine, Doxylamine brand name: Mersyndol.

Moderate Interaction
Medically reviewed by · Updated September 2026
The bottom line Moderate

Cnidium has a moderate interaction with Acetaminophen, Codeine, Doxylamine. In laboratory research, cnidium has been shown to have sedative and hypnotic effects, possibly related to constituent coumarins.

Read the full interaction report
SeverityModerate
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Cnidium and Acetaminophen, Codeine, Doxylamine

Here is the interaction we found between these two, with the evidence behind it.

Moderate

CNS DEPRESSANTS

Why this applies to Acetaminophen, Codeine, Doxylamine

Acetaminophen, Codeine, Doxylamine falls under CNS DEPRESSANTS — the group Cnidium interacts with.

In laboratory research, cnidium has been shown to have sedative and hypnotic effects, possibly related to constituent coumarins. Theoretically, cnidium may potentiate the effects of barbiturates, other sedatives, and anxiolytics.
Severity Moderate Likelihood Possible Evidence D

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the thing to keep in mind: your Mersyndol already contains two ingredients that calm down the brain. Codeine is an opioid pain reliever, and doxylamine is a sedating antihistamine. Both can make you drowsy on their own. In lab and animal studies, cnidium showed sedative effects, likely from its natural coumarin compounds. So in theory, pairing it with this medicine could stack the sleepiness.

What that might look like in real life is feeling extra groggy, foggy, dizzy, or slowed down, which matters before driving or anything that needs focus. I'll be honest though, this is only a theoretical concern based on early research, not human studies. Still, since both can sedate, it's worth a quick chat with your pharmacist before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Sun Y, Yang AWH, Lenon GB. Phytochemistry, ethnopharmacology, pharmacokinetics and toxicology of Cnidium monnieri (L.) Cusson. Int J Mol Sci. 2020;21(3):1006. PubMed

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Cnidium Also Interacts With Other Medications

Cnidium has 350 moderate known drug interactions in our database — the Acetaminophen, Codeine, Doxylamine one above is one of them. If you take anything else, check it against the full list below.

Moderate 350 No known interaction 2,480 (incl. Acetaminophen, Codeine, Doxylamine)
Taking anything else?

Check Another of Your Medications Against Cnidium

Covers the 2,830 medications we’ve checked against Cnidium. Pick one to open its full report.

Everything else you take

See Every Supplement That Interacts With Acetaminophen, Codeine, Doxylamine

This page covers Cnidium only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Acetaminophen, Codeine, Doxylamine page lists 261 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: 1,4-butanediol (major), Activated Charcoal (major), Asarabacca (major), Beer (major) and Gamma-hydroxybutyrate (ghb) (major).

By severity: 11 major · 208 moderate · 42 minor.

From our pharmacist’s overview on the Acetaminophen, Codeine, Doxylamine page

“Mersyndol pairs acetaminophen with codeine and doxylamine, two sedating drugs in one tablet, so I read its interaction list with genuine vigilance. Of the 261 supplements and herbs on file, the biggest hazard is anything else that slows the brain: 78 ingredients add sedation, and that group holds several of the 11 major-rated entries,…”

Reviewed by 2 · Jul 18, 2026

Open the Acetaminophen, Codeine, Doxylamine interaction page

One more smart check

Taking Cnidium as Part of a Dietary Supplement Product? Check It for Interactions

We hold 175 real supplement products containing Cnidium, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Cnidium. Your product may carry other ingredients that interact with Acetaminophen, Codeine, Doxylamine too, on top of Cnidium — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Cnidium and Acetaminophen, Codeine, Doxylamine Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Cnidium
Top half

#472 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Acetaminophen, Codeine, Doxylamine
Steady interest

#1,606 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Supplement

About Cnidium

What is Cnidium?

Cnidium
  • Skin conditions and itching
  • Erectile dysfunction and low libido
  • Eczema and dermatitis
  • Antifungal or antimicrobial washes
  • Athletic performance
  • General antioxidant support

Cnidium is the dried fruit of an Asian plant long used in traditional Chinese medicine, mostly for skin problems and sexual health. Modern human evidence for these uses is very limited, with most research coming from laboratory and animal studies. Talk with your pharmacist or doctor before using it, and avoid it during pregnancy and breastfeeding.

Read the full Cnidium monograph & all interactions
Keep checking

Other Drugs & Cnidium

Browse every other medication we’ve checked against Cnidium — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
350Moderate
0Minor
2,479No known interaction
350 Moderate 2,479 No interaction
Moderate

350 interactions

Showing 60 of 350 moderate interactions — see all 350 on the Cnidium page.

No interaction 2,479 drugs checked — show the list

We also checked Cnidium against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,479 medications checked with no known interaction — see the full Cnidium list.

See the full Cnidium interactions page
See every supplement checked against Acetaminophen, Codeine, Doxylamine, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Cnidium monograph › Uses, safety, and every drug interaction in one place Acetaminophen, Codeine, Doxylamine supplement interactions › Every supplement checked against Acetaminophen, Codeine, Doxylamine, ranked by severity Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Cnidium and Acetaminophen, Codeine, Doxylamine Together: Common Questions

Can you take Cnidium with Acetaminophen, Codeine, Doxylamine?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Cnidium and Acetaminophen, Codeine, Doxylamine interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Acetaminophen, Codeine, Doxylamine and Cnidium?

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.