Drug & supplement interaction

Karaya Gum + Macitentan, Tadalafil

Macitentan, Tadalafil brand name: Opsynvi.

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

Karaya Gum has a minor interaction with Macitentan, Tadalafil. Co-administration of oral drugs with bulk forming laxatives such as karaya gum may decrease, increase, or have no effect on the absorption of drugs.

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

Karaya Gum and Macitentan, Tadalafil

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

Minor

ORAL DRUGS

Why this applies to Macitentan, Tadalafil

Macitentan, Tadalafil falls under ORAL DRUGS — the group Karaya Gum interacts with.

Co-administration of oral drugs with bulk forming laxatives such as karaya gum may decrease, increase, or have no effect on the absorption of drugs. To avoid changes in absorption, take karaya gum 30-60 minutes after oral medications.
Severity Minor 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 picture with Opsynvi (macitentan plus tadalafil). Karaya gum is a fiber-type laxative that swells into a thick gel in your gut. Any time you have that kind of bulky gel sitting in your stomach and intestines, it can loosely bind to pills or slow them down, which could change how much medicine actually gets absorbed. In theory that might mean a little less of your dose reaches your blood, so the pill works less well, or occasionally a bit more.

The good news is this is a theoretical concern based on how fiber behaves, not something proven to cause real problems with this specific combo. The simple fix is timing: take your Opsynvi first, then wait about 30 to 60 minutes before your karaya gum. If you notice more swelling, headache, or lower blood pressure symptoms, or your pulmonary hypertension feels less controlled, check in with your pharmacist or doctor.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  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.

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

Karaya Gum Also Interacts With Other Medications

Karaya Gum has 2,021 minor known drug interactions in our database — the Macitentan, Tadalafil one above is one of them. If you take anything else, check it against the full list below.

Minor 2,021 No known interaction 809 (incl. Macitentan, Tadalafil)
Taking anything else?

Check Another of Your Medications Against Karaya Gum

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

Everything else you take

See Every Supplement That Interacts With Macitentan, Tadalafil

This page covers Karaya Gum only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Macitentan, Tadalafil page lists 264 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), American Mistletoe (major), Beer (major) and Grapefruit (major).

By severity: 10 major · 215 moderate · 39 minor.

From our pharmacist’s overview on the Macitentan, Tadalafil page

“Opsynvi pairs macitentan and tadalafil to lower pressure in the lung arteries, so anything that drops blood pressure further or shifts how the body handles these drugs deserves genuine respect, and I would read this list carefully. Ten of the 264 ingredients rate major, and most of the rest fall into two camps: additive blood-pressure-…”

Reviewed by 2 · Jul 18, 2026

Open the Macitentan, Tadalafil interaction page

One more smart check

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

We hold 16 real supplement products containing Karaya Gum, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Karaya Gum. Your product may carry other ingredients that interact with Macitentan, Tadalafil too, on top of Karaya Gum — 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 Karaya Gum and Macitentan, Tadalafil 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 Karaya Gum
Top half

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

29 days ago today
Medication Macitentan, Tadalafil
Top half

#1,262 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 Karaya Gum

What is Karaya Gum?

Karaya Gum
  • Constipation (bulk-forming laxative)
  • Appetite and weight management (bulking agent)
  • Dental adhesive/denture fixative
  • Skin barrier for ostomy appliances
  • Food thickening and stabilizing

Karaya gum is a natural plant gum from the Sterculia tree that is mostly used as a bulk-forming laxative and as a thickener or adhesive in food, dental, and ostomy products. As a fiber-type laxative it may help with occasional constipation, but high-quality evidence is limited, and it should be taken with plenty of water to avoid choking or blockage. Talk to your pharmacist or doctor before using it, especially if you have swallowing problems or bowel conditions.

Read the full Karaya Gum monograph & all interactions
Keep checking

Other Drugs & Karaya Gum

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

0Major
0Moderate
2,021Minor
808No known interaction
2,021 Minor 808 No interaction
Minor

2,021 interactions

Showing 60 of 2,021 minor interactions — see all 2,021 on the Karaya Gum page.

No interaction 808 drugs checked — show the list

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

Showing the 60 most looked-up of 808 medications checked with no known interaction — see the full Karaya Gum list.

See the full Karaya Gum interactions page
See every supplement checked against Macitentan, Tadalafil, 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
Karaya Gum monograph › Uses, safety, and every drug interaction in one place Macitentan, Tadalafil supplement interactions › Every supplement checked against Macitentan, Tadalafil, 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 Karaya Gum and Macitentan, Tadalafil Together: Common Questions

Can you take Karaya Gum with Macitentan, Tadalafil?
There is only a minor interaction, which is usually not serious. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Karaya Gum and Macitentan, Tadalafil interaction?
We rate it Minor. This interaction is generally not clinically significant, but it remains worth noting and discussing with your pharmacist.

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

Still Have a Question About Macitentan, Tadalafil and Karaya Gum?

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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.