Drug & supplement interaction

Huperzine A + Carbachol

Carbachol brand name: Carbastat.

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

Huperzine A has a moderate interaction with Carbachol. Theoretically, concurrent use of huperzine A with cholinergic drugs might increase the effects and side effects of these medications.

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

Huperzine A and Carbachol

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

Moderate

CHOLINERGIC DRUGS

Why this applies to Carbachol

Carbachol falls under CHOLINERGIC DRUGS — the group Huperzine A interacts with.

Theoretically, concurrent use of huperzine A with cholinergic drugs might increase the effects and side effects of these medications.
Huperzine A can inhibit acetylcholinesterase (AChE) and might cause cumulative effects if used with cholinergic drugs.
Severity Moderate Likelihood Possible Evidence B

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

Carbachol is a cholinergic medicine, meaning it boosts the activity of acetylcholine in the body. It's most often used as eye drops to lower pressure in glaucoma or to constrict the pupil during eye surgery. Huperzine A works in a related way: it blocks the enzyme that normally breaks down acetylcholine, so cholinergic signals stick around longer.

Put them together and you could get an additive, stacked-up cholinergic effect. With Carbachol that might mean things like extra eye irritation, headache, watery eyes, blurred or dim vision, or in stronger cases body-wide signs such as sweating, drooling, an upset stomach, or a slower heartbeat. This is a theoretical concern, but since both push cholinergic activity, it's worth running past your pharmacist or doctor before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Skolnick AA. Old Chinese herbal medicine used for fever yields possible new Alzheimer Disease therapy. JAMA 1997;277:776. DOI

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

Huperzine A Also Interacts With Other Medications

Huperzine A has 218 moderate known drug interactions in our database — the Carbachol one above is one of them. If you take anything else, check it against the full list below.

Moderate 218 No known interaction 2,612 (incl. Carbachol)
Taking anything else?

Check Another of Your Medications Against Huperzine A

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

Everything else you take

See Every Supplement That Interacts With Carbachol

This page covers Huperzine A only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Carbachol page lists 38 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Bacopa (moderate), Bael (moderate), Betel Nut (moderate) and Boxwood (moderate).

By severity: 1 major · 27 moderate · 10 minor.

From our pharmacist’s overview on the Carbachol page

“Activated charcoal is the entry to understand first for anyone using carbachol (Carbastat), a cholinergic eye medicine that lowers pressure in glaucoma and during eye surgery. Charcoal can soak up many drugs and cut how much reaches the body, and it holds the only major rating among the 38 supplements and herbs on file here.”

Reviewed by 2 · Jul 18, 2026

Open the Carbachol interaction page

One more smart check

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

We hold 86 real supplement products containing Huperzine A, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Huperzine A. Your product may carry other ingredients that interact with Carbachol too, on top of Huperzine A — 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 Huperzine A and Carbachol 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 Huperzine A
Top half

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

29 days ago today
Medication Carbachol
Steady interest

#2,601 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 Huperzine A

What is Huperzine A?

Huperzine A
  • Memory and cognitive support
  • Alzheimer's disease and dementia
  • Age-related memory decline
  • Focus and mental performance
  • Myasthenia gravis (traditional/older use)

Huperzine A is a purified compound from a Chinese clubmoss that acts like a mild cholinesterase inhibitor, similar in mechanism to some prescription Alzheimer's drugs. Some small studies suggest it may modestly help memory in people with dementia, but the evidence is limited and the quality is uncertain. Because it is biologically active and not well standardized, talk with a pharmacist or doctor before using it, and avoid it during pregnancy and breastfeeding.

Read the full Huperzine A monograph & all interactions
Keep checking

Other Drugs & Huperzine A

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

0Major
218Moderate
0Minor
2,611No known interaction
218 Moderate 2,611 No interaction
Moderate

218 interactions

Showing 60 of 218 moderate interactions — see all 218 on the Huperzine A page.

No interaction 2,611 drugs checked — show the list

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

Showing the 60 most looked-up of 2,611 medications checked with no known interaction — see the full Huperzine A list.

See the full Huperzine A interactions page
See every supplement checked against Carbachol, 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
Huperzine A monograph › Uses, safety, and every drug interaction in one place Carbachol supplement interactions › Every supplement checked against Carbachol, 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 Huperzine A and Carbachol Together: Common Questions

Can you take Huperzine A with Carbachol?
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 Huperzine A and Carbachol 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 Carbachol and Huperzine A?

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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.