Drug & supplement interaction

Goldenseal + Dorzolamide, Timolol

Dorzolamide, Timolol brand name: Cosopt.

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

Goldenseal has a moderate interaction with Dorzolamide, Timolol. Goldenseal might increase serum levels of drugs metabolized by CYP2D6.

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

Goldenseal and Dorzolamide, Timolol

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

Moderate

CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES

Why this applies to Dorzolamide, Timolol

Dorzolamide, Timolol falls under CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES — the group Goldenseal interacts with.

Goldenseal might increase serum levels of drugs metabolized by CYP2D6.
Clinical and in vitro research shows that goldenseal can significantly inhibit CYP2D6 enzymes, potentially increasing levels of drugs metabolized by CYP2D6.
Severity Moderate Likelihood Probable Evidence B

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 keep in mind with Cosopt: the timolol part is a beta blocker that your body normally clears using an enzyme called CYP2D6. Goldenseal can slow that enzyme down, so in theory more timolol could build up in your system than usual. Even though you put these drops in your eye, a small amount gets absorbed into your bloodstream.

If timolol levels creep up, you might notice a slower heart rate, lightheadedness, tiredness, or trouble breathing, especially if you have asthma or heart issues. The dose from eye drops is small, so this is more of a caution than an alarm. Still, before you pair goldenseal with Cosopt, I'd run it past your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Gurley BJ, Gardner SF, Hubbard MA, et al. In vivo effects of goldenseal, kava kava, black cohosh, and valerian on human cytochrome P450 1A2, 2D6, 2E1, and 3A4/5 phenotypes. Clin Pharmacol Ther 2005;77:415-26. PubMed
  2. Gurley BJ, Swain A, Hubbard MA, et al. Clinical assessement of CYP2D6-mediated herb-drug interactions in humans: Effects of milk-thistle, black cohosh, goldenseal, kava kava, St. John's wort, and Echinacea. Mol Nutr Food Res 2008;52:755-63.
  3. Sevior, D. K., Hokkanen, J., Tolonen, A., Abass, K., Tursas, L., Pelkonen, O., and Ahokas, J. T. Rapid screening of commercially available herbal products for the inhibition of major human hepatic cytochrome P450 enzymes using the N-in-one cocktail. Xeno 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

Goldenseal Also Interacts With Other Medications

Goldenseal has 1,235 moderate, 1 minor known drug interactions in our database — the Dorzolamide, Timolol one above is one of them. If you take anything else, check it against the full list below.

Moderate 1,235 Minor 1 No known interaction 1,594 (incl. Dorzolamide, Timolol)
Taking anything else?

Check Another of Your Medications Against Goldenseal

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

Everything else you take

See Every Supplement That Interacts With Dorzolamide, Timolol

This page covers Goldenseal only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Dorzolamide, Timolol page lists 71 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Indian Snakeroot (major), 1,3-dmaa (moderate), Acacia Rigidula (moderate), Active Hexose Correlated Compound (ahcc) (moderate) and Ayahuasca (moderate).

By severity: 1 major · 59 moderate · 11 minor.

From our pharmacist’s overview on the Dorzolamide, Timolol page

“Indian snakeroot is the one entry here I would treat as a genuine hazard with Cosopt (dorzolamide and timolol), the glaucoma eye drop. Its reserpine content plus a beta-blocker like timolol could slow the heart or drop blood pressure too far, and it holds the only major rating among the 71 supplements and herbs on file.”

Reviewed by 2 · Jul 18, 2026

Open the Dorzolamide, Timolol interaction page

One more smart check

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

We hold 1,726 real supplement products containing Goldenseal, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Goldenseal. Your product may carry other ingredients that interact with Dorzolamide, Timolol too, on top of Goldenseal — 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 Goldenseal and Dorzolamide, Timolol 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 Goldenseal
Top 25%

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

29 days ago today
Medication Dorzolamide, Timolol
Top half

#747 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 Goldenseal

What is Goldenseal?

Goldenseal
  • Digestive upset and diarrhea
  • Colds and respiratory infections
  • Sore throat and mouth sores
  • Skin and eye irritation (topical/traditional)
  • Antimicrobial support

Goldenseal is a popular North American herb that contains berberine, a compound studied for antimicrobial effects. However, strong human evidence for its many traditional uses is largely lacking, and it should be avoided during pregnancy and breastfeeding. Talk to a pharmacist or doctor before using it.

Read the full Goldenseal monograph & all interactions
Medication

About Dorzolamide and Timolol Ophthalmic

What Is Dorzolamide and Timolol Ophthalmic Used For?

Brand name: Cosopt

Dorzolamide and timolol ophthalmic eye drops are used to reduce elevated intraocular pressure (pressure inside the eye) in people with open-angle glaucoma or ocular hypertension (higher-than-normal eye pressure without signs of glaucoma damage). It is specifically intended for patients who have not responded well enough to beta-blocker eye drops alone.

This combination is available as Cosopt, Cosopt PF, and Dorzolamide Hydrochloride and Timolol Maleate eye drops. Cosopt PF is the preservative-free formulation, which may be preferred for people sensitive to preservatives.

See full Dorzolamide and Timolol Ophthalmic drug information
Keep checking

Other Drugs & Goldenseal

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

0Major
1,235Moderate
1Minor
1,593No known interaction
1,235 Moderate 1 Minor 1,593 No interaction
Moderate

1,235 interactions

Showing 60 of 1,235 moderate interactions — see all 1,235 on the Goldenseal page.

Minor

1 interaction

No interaction 1,593 drugs checked — show the list

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

Showing the 60 most looked-up of 1,593 medications checked with no known interaction — see the full Goldenseal list.

See the full Goldenseal interactions page
See every supplement checked against Dorzolamide, Timolol, 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
Goldenseal monograph › Uses, safety, and every drug interaction in one place Dorzolamide, Timolol supplement interactions › Every supplement checked against Dorzolamide, Timolol, ranked by severity Dorzolamide and Timolol Ophthalmic drug information › The full plain-English guide to this medication 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 Goldenseal and Dorzolamide, Timolol Together: Common Questions

Can you take Goldenseal with Dorzolamide, Timolol?
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 Goldenseal and Dorzolamide, Timolol 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 Dorzolamide, Timolol and Goldenseal?

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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.