Drug & supplement interaction

Quebracho Blanco + Macitentan

Macitentan brand name: Opsumit.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Oct 4, 2026
The bottom line No known interaction

We found no known interaction between Quebracho Blanco and Macitentan 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

Quebracho Blanco and Macitentan

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 Macitentan and Quebracho Blanco 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.

Worth understanding: our licensed dataset holds no drug-interaction record for Quebracho Blanco at all — not against Macitentan, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.

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.

Quebracho Blanco safety at a glance

Quebracho Blanco overall Use caution Limited human safety data and the bark contains active alkaloids, so use cautiously.
Pregnancy Avoid Not enough safety information; avoid use during pregnancy.
Breastfeeding Avoid No reliable safety data, so avoid while breastfeeding.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Macitentan and Quebracho Blanco? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

No Interaction Found — But Data Suggests Quebracho Blanco and Macitentan May Share a Side Effect

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.

  • Headache reported in 12.1% of FDA reports for Macitentan Additional detail

    Quebracho Blanco

    “Orally, quebracho blanco seems to be well tolerated. However, a thorough evaluation of safety outcomes has not been conducted. Some people who take quebracho blanco bark may experience salivation, headache, outbreaks of sweating, vertigo, stupor, and drowsiness. In large doses, it can cause nausea and vomiting (18).”

    Quebracho Blanco · Natural Medicines adverse-effect record, reported in cluster headache.

    1 source cited
    1. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.

    “Orally, quebracho blanco bark may cause headache, vertigo, stupor, and drowsiness (18).”

    Quebracho Blanco · Natural Medicines adverse-effect record, reported in cluster headache.

    1 source cited
    1. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.

    Macitentan

    Listed in the ADVERSE REACTIONS section of the FDA label for Macitentan, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

Reported for Quebracho Blanco but not commonly for Macitentan: drowsiness, vomiting, sweating and dizziness.

Effects for Macitentan come from the ADVERSE REACTIONS section of its FDA label; effects for Quebracho Blanco come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 68,860 voluntary FDA FAERS reports for Macitentan that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Everything else you take

See Every Supplement That Interacts With Macitentan

This page covers Quebracho Blanco only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Macitentan page lists 253 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: 9 major · 205 moderate · 39 minor.

From our pharmacist’s overview on the Macitentan page

“If you take macitentan (Opsumit) for pulmonary arterial hypertension, study this page rather than skim it. It lists 253 supplement and herbal ingredients, nine rated major.”

Reviewed by 2 · Jul 18, 2026

Open the Macitentan interaction page

How much people look this up

Where Quebracho Blanco and Macitentan 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 Quebracho Blanco
Top half

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

29 days ago today
Medication Macitentan
Top 25%

#507 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 Quebracho Blanco reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified October 4, 2026. The Quebracho Blanco and Macitentan 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 Quebracho Blanco

What is Quebracho Blanco?

  • Coughs and breathing problems
  • Asthma and bronchitis symptoms
  • Altitude or shortness of breath
  • Erectile dysfunction (traditional)
  • Fever and digestive upset

Quebracho Blanco is the bark of a South American tree traditionally used for breathing problems and coughs, but high-quality human studies are lacking. It contains alkaloids that may affect blood vessels and breathing, so safety is not well established—talk to your pharmacist or doctor before using it.

Aspidosperma quebracho-blanco · Apocynaceae · Bark · Tincture, liquid extract, dried bark for tea, capsules

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

Quebracho Blanco: dosing

There is no well-established or standardized dose for quebracho blanco. The amount of active alkaloids can vary a lot between products, which makes safe dosing hard to determine.If you choose to use a quebracho product, follow the directions on the label and do not exceed the recommended amount.

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

Read the full Quebracho Blanco monograph & all interactions
Medication

About Macitentan

What Is Macitentan Used For?

Brand name: Opsumit

Macitentan tablets — sold under the brand name Opsumit — are used to treat pulmonary arterial hypertension (PAH, WHO Group I), a type of high blood pressure in the arteries of the lungs. The goal is to slow the disease from getting worse and to lower the chance of being hospitalized because of PAH.

In the key clinical study, macitentan was used in adults with mainly moderate-to-severe PAH symptoms. Patients had PAH caused by unknown or inherited causes, connective tissue disorders, or congenital heart disease with repaired shunts.

Most-Reported Side Effects for Macitentan

From FAERS, the FDA’s public side-effect reporting system (68,860 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Dyspnea 11,958 reports
Headache 8,323 reports
Diarrhea 6,584 reports
Nausea 5,972 reports
Fatigue 5,041 reports
See full Macitentan drug information
Keep checking

Other Drugs & Quebracho Blanco

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

0Major
0Moderate
0Minor
2,829No known interaction
2,829 No interaction
No interaction 2,829 drugs checked — show the list

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

Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full Quebracho Blanco list.

See the full Quebracho Blanco interactions page
See every supplement checked against Macitentan, ranked by severity
Evidence & sources

Quebracho Blanco References

The 1 references that drive our Quebracho Blanco 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. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.

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 Quebracho Blanco and Macitentan Together: Common Questions

Is it safe to take Quebracho Blanco with Macitentan?
We do not list a known interaction between Quebracho Blanco and Macitentan. 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 Quebracho Blanco and Macitentan have any of the same side effects?
Yes — our sources link each of them separately to one 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.
Does Macitentan interact with any supplements?
Yes. Macitentan has documented interactions with 253 supplements in our database — Quebracho Blanco is not one of them. The Macitentan 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

Quebracho Blanco monograph Uses, safety profile, and every drug interaction in one place Macitentan drug information The full plain-English guide to this medication Macitentan supplement interactions Every supplement checked against Macitentan, 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 1 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Macitentan and Quebracho Blanco?

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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.