Drug & supplement interaction

Shepherd's Purse + Codeine, Papaverine

Codeine, Papaverine brand name: Copavin.

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

Shepherd's Purse has a moderate interaction with Codeine, Papaverine. Theoretically, concomitant use with drugs with sedative properties may cause additive effects and side effects.

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

Shepherd's Purse and Codeine, Papaverine

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

Moderate

CNS DEPRESSANTS

Why this applies to Codeine, Papaverine

Codeine, Papaverine falls under CNS DEPRESSANTS — the group Shepherd's Purse interacts with.

Theoretically, concomitant use with drugs with sedative properties may cause additive effects and side effects.
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 practical takeaway. Copavin combines codeine (an opioid pain reliever and cough suppressant) with papaverine. Codeine in particular can make you drowsy, slow your breathing, and leave you feeling foggy or lightheaded. Shepherd's purse has traditionally been linked to a mild calming or sedative-like effect, so the concern is simply that the two together might add up and leave you sleepier than expected.

I'll be honest with you, though: this is a theoretical caution based on how these things might behave, not on strong human studies. It's not about shepherd's purse changing how your body breaks codeine down. Still, if you notice extra drowsiness, dizziness, or feel unusually out of it, take it easy and check in with your pharmacist or doctor before combining them regularly.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.

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

Shepherd's Purse Also Interacts With Other Medications

Shepherd's Purse has 263 moderate known drug interactions in our database — the Codeine, Papaverine one above is one of them. If you take anything else, check it against the full list below.

Moderate 263 No known interaction 2,567 (incl. Codeine, Papaverine)
Taking anything else?

Check Another of Your Medications Against Shepherd's Purse

Covers the 2,830 medications we’ve checked against Shepherd's Purse. Pick one to open its full report.

Everything else you take

See Every Supplement That Interacts With Codeine, Papaverine

This page covers Shepherd's Purse only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Codeine, Papaverine page lists 145 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), American Mistletoe (major), Beer (major) and Gamma-hydroxybutyrate (ghb) (major).

By severity: 8 major · 114 moderate · 23 minor.

From our pharmacist’s overview on the Codeine, Papaverine page

“Codeine combined with papaverine (Copavin) is an opioid product, and I read its supplement list as one that calls for genuine care. More than half of the 145 entries pile sedation on top of the drug's own, and the standouts are everyday alcohol (beer and wine each carry a major rating, well documented in people) and kava, combinations…”

Reviewed by 2 · Jul 18, 2026

Open the Codeine, Papaverine interaction page

One more smart check

Taking Shepherd's Purse as Part of a Dietary Supplement Product? Check It for Interactions

We hold 73 real supplement products containing Shepherd's Purse, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Shepherd's Purse. Your product may carry other ingredients that interact with Codeine, Papaverine too, on top of Shepherd's Purse — 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 Shepherd's Purse and Codeine, Papaverine 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 Shepherd's Purse
Steady interest

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

29 days ago today
Medication Codeine, Papaverine
Steady interest

#1,752 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 Shepherd's Purse

What is Shepherd's Purse?

Shepherd's Purse
  • Heavy or prolonged menstrual bleeding
  • Minor bleeding (nosebleeds, wounds)
  • Mild diuretic
  • Digestive complaints
  • After-childbirth bleeding (traditional)

Shepherd's purse is a traditional herb most often used to help slow heavy menstrual bleeding and other minor bleeding, but solid human research is very limited. Because it may affect blood clotting, blood pressure, and the uterus, it should be avoided during pregnancy and used cautiously under professional guidance.

Read the full Shepherd's Purse monograph & all interactions
Keep checking

Other Drugs & Shepherd's Purse

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

0Major
263Moderate
0Minor
2,566No known interaction
263 Moderate 2,566 No interaction
Moderate

263 interactions

Showing 60 of 263 moderate interactions — see all 263 on the Shepherd's Purse page.

No interaction 2,566 drugs checked — show the list

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

Showing the 60 most looked-up of 2,566 medications checked with no known interaction — see the full Shepherd's Purse list.

See the full Shepherd's Purse interactions page
See every supplement checked against Codeine, Papaverine, 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
Shepherd's Purse monograph › Uses, safety, and every drug interaction in one place Codeine, Papaverine supplement interactions › Every supplement checked against Codeine, Papaverine, 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 Shepherd's Purse and Codeine, Papaverine Together: Common Questions

Can you take Shepherd's Purse with Codeine, Papaverine?
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 Shepherd's Purse and Codeine, Papaverine 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 Codeine, Papaverine and Shepherd's Purse?

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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.