Drug & supplement interaction

Black Psyllium + Dorzolamide, Timolol

Dorzolamide, Timolol brand name: Cosopt.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between Black Psyllium and Dorzolamide, Timolol in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Black Psyllium and Dorzolamide, Timolol

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Dorzolamide, Timolol and Black Psyllium in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Black Psyllium safety at a glance

Black Psyllium overall Use caution Generally well tolerated when taken with enough water, but it can cause choking or blockage if fluids are inadequate.
Pregnancy Likely Safe When used orally with appropriate fluid intake. Read the full pregnancy detail
Breastfeeding Likely Safe When used orally with appropriate fluid intake. Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Dorzolamide, Timolol and Black Psyllium? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Dorzolamide, Timolol

Interactions in our licensed database are recorded against drug classes, not just single drug names. Dorzolamide, Timolol is filed under 4 classifications — including beta-blockers, cytochrome p450 2d6 (cyp2d6) substrates, topical drugs. Black Psyllium has documented interactions with 7 drug classes — the most serious being carbamazepine (tegretol) (moderate), lithium (moderate) and metformin (glucophage) (moderate) — and none of Dorzolamide, Timolol’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Black Psyllium Does Interact With Other Medications

Black Psyllium has 23 moderate, 2,002 minor known drug interactions in our database — Dorzolamide, Timolol isn’t one of them. If you take anything else, check it against the full list below.

Moderate 23 Minor 2,002 No known interaction 805 (incl. Dorzolamide, Timolol)
Taking anything else?

Check Another of Your Medications Against Black Psyllium

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

What to actually watch for

No Interaction Found — But Data Suggests Black Psyllium and Dorzolamide, Timolol May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do. 2 of them are worth acting on rather than waiting out — marked below.

  • Wheezing / An allergic reaction Worth acting on Additional detail

    Black Psyllium

    “Several psyllium species have been associated with sensitization and allergic reactions, especially in people exposed to airborne psyllium dust, such as nurses preparing doses of psyllium powder, and workers in psyllium processing plants. Symptoms of occupational exposure include rhinitis, conjunctivitis, wheezing, asthma, and urticarial rashes (18,93214).”

    Black Psyllium · Natural Medicines adverse-effect record, reported in asthma.

    5 sources cited
    1. 93214. Semen plantaginis in: WHO Monographs on Selected Medicinal Plants, volume 1. World Health Organization, Geneva, 1999. Available at http://apps.who.int/medicinedocs/en/d/Js2200e/. Accessed November 26, 1026.
    2. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
    3. 2329. Vaswani SK, Hamilton RG, Valentine MD, Adkinson NF. Psyllium laxative-induced anaphylaxis, asthma, and rhinitis. Allergy 1996;51:266-8. PubMed
    4. 8079. Lantner RR, Espiritu BR, Zumerchik P, Tobin MC. Anaphylaxis following ingestion of a psyllium-containing cereal. JAMA 1990;264:2534-6. DOI
    5. 9246. Kaplan MJ. Anaphylactic reaction to "Heartwise." N Engl J Med 1990;323:1072-3. DOI

    Dorzolamide, Timolol

    Listed in the ADVERSE REACTIONS section of the FDA label for Dorzolamide, Timolol. Read the label on DailyMed ›

  • A stuffy or runny nose Additional detail

    Black Psyllium

    Recorded for Black Psyllium in the same Natural Medicines adverse-effect record shown under Wheezing / An allergic reaction above.

    Dorzolamide, Timolol

    Listed in the ADVERSE REACTIONS section of the FDA label for Dorzolamide, Timolol. Read the label on DailyMed ›

Reported for Black Psyllium but not commonly for Dorzolamide, Timolol: a bowel blockage and bloating or gas.

Effects for Dorzolamide, Timolol come from the ADVERSE REACTIONS section of its FDA label; effects for Black Psyllium come from the Natural Medicines adverse-effect record, quoted above. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Special populations

Black Psyllium in Pregnancy & Breastfeeding

Pregnancy And Lactation Likely Safe

When used orally with appropriate fluid intake.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

Overlapping uses

What Dorzolamide, Timolol Is Prescribed For, and What Black Psyllium Has Been Studied For

These two come up together because they touch the same health topic — not because they do the same job. Dorzolamide, Timolol is a prescription medicine with approved uses on its FDA label. Black Psyllium is a supplement: what follows is what researchers have looked at it for, and how strong that evidence is.

Dorzolamide, Timolol is prescribed for: 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.

Black Psyllium has been studied for:

  • Hypertension studied, not established Black Psyllium has been studied for this. Natural Medicines rates the evidence: Insufficient Reliable Evidence To Rate Read what the research shows

    Black Psyllium for hypertension

    It is unclear if oral black psyllium is beneficial in patients with hypertension.

Effectiveness ratings and the research summaries above are the verbatim record from the Natural Medicines database, which grades evidence from “Effective” down to “Insufficient Reliable Evidence To Rate”. A rating below the top of that scale means researchers have looked at it — not that it works, and never that it can stand in for a prescribed medicine. Do not stop or replace Dorzolamide, Timolol on your own; if you are taking Black Psyllium for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.

Everything else you take

See Every Supplement That Interacts With Dorzolamide, Timolol

This page covers Black Psyllium 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 Black Psyllium as Part of a Dietary Supplement Product? Check It for Interactions

We hold 5 real supplement products containing Black Psyllium, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Black Psyllium. Even though Black Psyllium itself has no known interaction with Dorzolamide, Timolol, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Black Psyllium 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 Black Psyllium
Top half

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

29 days ago today
Medication Dorzolamide, Timolol
Top 25%

#381 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.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Black Psyllium reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Black Psyllium and Dorzolamide, Timolol records this page draws on were last updated July 10, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Supplement

About Black Psyllium

What is Black Psyllium?

Black Psyllium
  • Constipation
  • Diarrhea
  • High cholesterol
  • Digestive health
  • Blood sugar support
  • Weight management

Black psyllium is a soluble-fiber supplement made from the seeds of a Plantago plant, used mostly to ease constipation and support digestive health. It is best known and most studied for relieving constipation and may modestly help lower cholesterol, but it must always be taken with plenty of water. Talk with your pharmacist or doctor before starting, especially if you have swallowing problems or bowel disorders.

Plantago psyllium · Plantaginaceae · Seeds and seed husk · Powder, capsules, granules, whole seeds, wafers

An interaction check asks whether these two react with each other — it does not ask whether Black Psyllium is a good idea for someone in your situation. Here is what our Black Psyllium record says about it on its own.

Black Psyllium: dosing

There is no single official dose of black psyllium for everyone, and the right amount depends on the product and the reason you are using it. Because products differ in strength and form, the best approach is to follow the directions on the label.A general principle with all psyllium products is to mix the dose in a full glass of water or other liquid and drink it right away, then drink more water afterward. They can help you choose the right product and dose.

From our Black Psyllium monograph — the full record covers uses, side effects and every documented interaction.

Read the full Black Psyllium 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 & Black Psyllium

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

0Major
23Moderate
2,002Minor
804No known interaction
23 Moderate 2,002 Minor 804 No interaction
Moderate

23 interactions

Minor

2,002 interactions

Showing 60 of 2,002 minor interactions — see all 2,002 on the Black Psyllium page.

No interaction 804 drugs checked — show the list

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

Showing the 60 most looked-up of 804 medications checked with no known interaction — see the full Black Psyllium list.

See the full Black Psyllium interactions page
See every supplement checked against Dorzolamide, Timolol, ranked by severity
Evidence & sources

Black Psyllium References

The 18 references that drive our Black Psyllium monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
  2. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
  3. Covington TR, et al. Handbook of Nonprescription Drugs. 11th ed. Washington, DC: American Pharmaceutical Association, 1996.
  4. Etman M. Effect of a bulk forming laxative on the bioavailablility of carbamazepine in man. Drug Dev Ind Pharm 1995;21:1901-6.
  5. Perlman BB. Interaction between lithium salts and ispaghula husk. Lancet 1990;335:416.
  6. Vaswani SK, Hamilton RG, Valentine MD, Adkinson NF. Psyllium laxative-induced anaphylaxis, asthma, and rhinitis. Allergy 1996;51:266-8. PubMed
  7. Lantner RR, Espiritu BR, Zumerchik P, Tobin MC. Anaphylaxis following ingestion of a psyllium-containing cereal. JAMA 1990;264:2534-6. DOI
  8. Kaplan MJ. Anaphylactic reaction to "Heartwise." N Engl J Med 1990;323:1072-3. DOI
  9. Nordstrom M, Melander A, Robertsson E, Steen B. Influence of wheat bran and of a bulk-forming ispaghula cathartic on the bioavailability of digoxin in geriatric in-patients. Drug Nutr Interact 1987;5:67-9..
  10. Robinson DS, Benjamin DM, McCormack JJ. Interaction of warfarin and nonsystemic gastrointestinal drugs. Clin Pharmacol Ther 1971;12:491-5. PubMed
  11. Garcia JJ, Fernandez N, Diez MJ, et al. Influence of two dietary fibers in the oral bioavailability and other pharmacokinetic parameters of ethinyloestradiol. Contraception 2000;62:253-7. PubMed
  12. Fernandez N, Lopez C, Díez R, et al. Drug interactions with the dietary fiber Plantago ovata husk. Expert Opin Drug Metab Toxicol 2012;8(11):1377-86.
  13. Semen plantaginis in: WHO Monographs on Selected Medicinal Plants, volume 1. World Health Organization, Geneva, 1999. Available at http://apps.who.int/medicinedocs/en/d/Js2200e/. Accessed November 26, 1026.
  14. Code of Federal Regulations, Title 21 (21CFR 101.17). Food labeling warning, notice, and safe handling statements. Available at www.ecfr.gov/cgi-bin/text-idx?SID=20f647d3b74161501f46564b915b4048&mc=true&node=se21.2.101_117&rgn=div8. Accessed December 3, 2
  15. Code of Federal Regulations, Title 21 (21CFR 201.319). Specific labeling requirements - water-soluble gums, hydrophilic gums, and hydrophilic mucilloids. Available at www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=201.319. Accessed Dece

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Black Psyllium and Dorzolamide, Timolol Together: Common Questions

Is it safe to take Black Psyllium with Dorzolamide, Timolol?
We do not list a known interaction between Black Psyllium and Dorzolamide, Timolol. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
Do Black Psyllium and Dorzolamide, Timolol have any of the same side effects?
Yes — our sources link each of them separately to 3 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
Are Black Psyllium and Dorzolamide, Timolol used for the same thing?
They overlap in purpose, which usually means the real question is whether you need both rather than whether they are safe together. This page lists the shared uses and how strong the evidence is for Black Psyllium in each. That is a conversation for your prescriber, especially if Dorzolamide, Timolol is being adjusted to a target.
How was the Black Psyllium and Dorzolamide, Timolol combination checked?
Interactions in our licensed database are recorded against drug classes. Dorzolamide, Timolol is filed under 4 classifications, and Black Psyllium has documented interactions with 7 drug classes — none of Dorzolamide, Timolol's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Black Psyllium interact with any other medications?
Yes. Black Psyllium has 2,025 documented drug interactions in our database — Dorzolamide, Timolol is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Dorzolamide, Timolol interact with any supplements?
Yes. Dorzolamide, Timolol has documented interactions with 71 supplements in our database — Black Psyllium is not one of them. The Dorzolamide, Timolol interaction page linked on this page lists every one, ranked by severity.

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

Where next

Keep Exploring

Black Psyllium monograph Uses, safety profile, and every drug interaction in one place Dorzolamide and Timolol Ophthalmic drug information The full plain-English guide to this medication Dorzolamide, Timolol supplement interactions Every supplement checked against Dorzolamide, Timolol, 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 References The 18 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

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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.