Drug & supplement interaction

Henbane + Chlorpheniramine, Methscopolamine, Phenylephrine

Chlorpheniramine, Methscopolamine, Phenylephrine brand names: DA II, Extendryl JR, Dallergy, Extendryl SR, Extendryl Chews, and others.

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

Henbane has a major interaction with Chlorpheniramine, Methscopolamine, Phenylephrine. Concomitant use of henbane can have additive anticholinergic effects and adverse effects with amantadine, antihistamines, atropine, belladonna alkaloids, hyoscyamine, phenothiazines, procainamide, scopolamine, and tricyclic antidepressants.

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

Henbane and Chlorpheniramine, Methscopolamine, Phenylephrine

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

Major

ANTICHOLINERGIC DRUGS

Why this applies to Chlorpheniramine, Methscopolamine, Phenylephrine

Chlorpheniramine, Methscopolamine, Phenylephrine falls under ANTICHOLINERGIC DRUGS — the group Henbane interacts with.

Concomitant use of henbane can have additive anticholinergic effects and adverse effects with amantadine, antihistamines, atropine, belladonna alkaloids, hyoscyamine, phenothiazines, procainamide, scopolamine, and tricyclic antidepressants.
Severity Major Likelihood Probable Evidence D

Interaction 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..

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

Here's the thing to know about combining henbane with this combo product: two of its ingredients already work the same way henbane does. Methscopolamine is an anticholinergic (it dries up secretions), and chlorpheniramine, an older antihistamine, also has anticholinergic effects of its own. Henbane is loaded with tropane alkaloids like scopolamine and atropine that block the very same acetylcholine signaling. Stack them together and the effects pile up.

That means you could see more dry mouth, blurry vision, constipation, urinary retention, confusion, fast heartbeat, and trouble sweating in the heat. This concern is based on how these compounds behave rather than firm studies, but it's a real and reasonable worry. Honestly, henbane isn't safe to self-dose at all. Please talk with your pharmacist or doctor before mixing the two.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Trans. S. Klein. Boston, MA: American Botanical Council, 1998.

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

Henbane Also Interacts With Other Medications

Henbane has 194 major, known drug interactions in our database — the Chlorpheniramine, Methscopolamine, Phenylephrine one above is one of them. If you take anything else, check it against the full list below.

Major 194 No known interaction 2,636 (incl. Chlorpheniramine, Methscopolamine, Phenylephrine)
Taking anything else?

Check Another of Your Medications Against Henbane

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

Everything else you take

See Every Supplement That Interacts With Chlorpheniramine, Methscopolamine, Phenylephrine

This page covers Henbane only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Chlorpheniramine, Methscopolamine, Phenylephrine page lists 230 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Ephedra (major), Grapefruit (major), Lithium (major) and Peyote (major).

By severity: 10 major · 175 moderate · 45 minor.

From our pharmacist’s overview on the Chlorpheniramine, Methscopolamine, Phenylephrine page

“This allergy and congestion combination, Chlorpheniramine, Methscopolamine, and Phenylephrine (Dallergy, Extendryl), has 230 supplement and herbal ingredients on its interaction list, and 10 of them carry major ratings, so this is a list to check carefully rather than skim. The largest group works through the liver enzyme that breaks t…”

Reviewed by 2 · Jul 18, 2026

Open the Chlorpheniramine, Methscopolamine, Phenylephrine interaction page

One more smart check

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

We hold 6 real supplement products containing Henbane, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Henbane. Your product may carry other ingredients that interact with Chlorpheniramine, Methscopolamine, Phenylephrine too, on top of Henbane — 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 Henbane and Chlorpheniramine, Methscopolamine, Phenylephrine 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 Henbane
Steady interest

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

29 days ago today
Medication Chlorpheniramine, Methscopolamine, Phenylephrine
Top half

#820 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 Henbane

What is Henbane?

Henbane
  • Pain relief
  • Muscle spasms and cramps
  • Sleep and sedation
  • Asthma and breathing problems (traditional)
  • Toothache (traditional)

Henbane is a highly poisonous plant containing potent alkaloids like hyoscyamine and scopolamine, and even small amounts can cause serious or deadly poisoning. While its compounds have real medical uses, these belong in carefully controlled prescription drugs, not in self-made or self-dosed herbal products. We strongly advise against using henbane as a supplement.

Read the full Henbane monograph & all interactions
Keep checking

Other Drugs & Henbane

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

194Major
0Moderate
0Minor
2,635No known interaction
194 Major 2,635 No interaction
Major

194 interactions

Showing 60 of 194 major interactions — see all 194 on the Henbane page.

No interaction 2,635 drugs checked — show the list

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

Showing the 60 most looked-up of 2,635 medications checked with no known interaction — see the full Henbane list.

See the full Henbane interactions page
See every supplement checked against Chlorpheniramine, Methscopolamine, Phenylephrine, 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
Henbane monograph › Uses, safety, and every drug interaction in one place Chlorpheniramine, Methscopolamine, Phenylephrine supplement interactions › Every supplement checked against Chlorpheniramine, Methscopolamine, Phenylephrine, 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 Henbane and Chlorpheniramine, Methscopolamine, Phenylephrine Together: Common Questions

Can you take Henbane with Chlorpheniramine, Methscopolamine, Phenylephrine?
This is rated a major interaction, so the combination is best avoided unless your doctor or pharmacist has specifically told you otherwise. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Henbane and Chlorpheniramine, Methscopolamine, Phenylephrine interaction?
We rate it Major. This is a clinically significant combination that is generally best avoided, or used only under the direct supervision of your physician or pharmacist.

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

Still Have a Question About Chlorpheniramine, Methscopolamine, Phenylephrine and Henbane?

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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.