Drug & supplement interaction

Hibiscus Sabdariffa + Macitentan, Tadalafil

Macitentan, Tadalafil brand name: Opsynvi.

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

Macitentan, Tadalafil falls into 3 drug categories that Hibiscus Sabdariffa can interact with; the most serious is rated moderate. Theoretically, taking Hibiscus sabdariffa with antihypertensive drugs might increase the risk of hypotension.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions3
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Hibiscus Sabdariffa and Macitentan, Tadalafil

These two interact in 3 distinct ways. Each one is explained separately below.

Why Are There 3 Interactions?

Hibiscus Sabdariffa interacts with whole categories of medication. Macitentan, Tadalafil falls into 3 of those categories, so it can interact with Hibiscus Sabdariffa in 3 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

ANTIHYPERTENSIVE DRUGS

1 of 3

Why this applies to Macitentan, Tadalafil

Macitentan, Tadalafil falls under ANTIHYPERTENSIVE DRUGS — the group Hibiscus Sabdariffa interacts with.

Theoretically, taking Hibiscus sabdariffa with antihypertensive drugs might increase the risk of hypotension.
Most clinical evidence suggests that taking Hibiscus sabdariffa reduces systolic and diastolic blood pressure. In animal research, Hibiscus sabdariffa increased the hypotensive effects of single doses of losartan and amlodipine.
Severity Moderate 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

Opsynvi combines two medicines that both lower pressure in the blood vessels feeding your lungs, and tadalafil in particular can nudge your overall blood pressure down too. Hibiscus, especially as a concentrated supplement, has its own gentle blood-pressure-lowering effect. Stack the two and the numbers could dip a little lower than expected. That might show up as feeling lightheaded, dizzy when you stand up quickly, unusually tired, or a bit flushed or headachy.

To be fair, this is a theoretical concern based on how these things work, not proven in people taking Opsynvi. A cup of tart hibiscus tea now and then is unlikely to cause trouble. Still, since your medicine already works on blood pressure, check with your pharmacist or doctor before using hibiscus supplements regularly.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. McKay DL, Chen CY, Saltzman E, Blumberg JB. Hibiscus Sabdariffa L. tea (tisane) lowers blood pressure in prehypertensive and mildly hypertensive adults. J Nutr 2010;140:298-303. PubMed
  2. Haji, Faraji M. and Haji, Tarkhani A. The effect of sour tea (Hibiscus sabdariffa) on essential hypertension. J.Ethnopharmacol. 1999;65(3):231-236. PubMed
  3. Mozaffari-Khosravi, H., Jalali-Khanabadi, B. A., Afkhami-Ardekani, M., Fatehi, F., and Noori-Shadkam, M. The effects of sour tea (Hibiscus sabdariffa) on hypertension in patients with type II diabetes. J Hum.Hypertens 2009;23(1):48-54. PubMed
  4. Ahad A, Raish M, Bin Jardan YA, Alam MA, Al-Mohizea AM, Al-Jenoobi FI. Effect of Hibiscus sabdariffa and Zingiber officinale on the antihypertensive activity and pharmacokinetic of losartan in hypertensive rats. Xenobiotica. 2020:1-11.
  5. Najafpour Boushehri S, Karimbeiki R, Ghasempour S, et al. The efficacy of sour tea (Hibiscus sabdariffa L.) on selected cardiovascular disease risk factors: A systematic review and meta-analysis of randomized clinical trials. Phytother Res. 2020;34(2):329
  6. Alam MA, Bin Jardan YA, Alzenaidy B, et al. Effect of Hibiscus sabdariffa and Zingiber officinale on pharmacokinetics and pharmacodynamics of amlodipine. J Pharm Pharmacol 2021;73(9):1151-60.
Minor

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES

2 of 3

Macitentan, Tadalafil also falls under CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES.

Theoretically, Hibiscus sabdariffa extract might reduce the metabolism of CYP2C9 substrates.
In vitro research shows that Hibiscus sabdariffa calyx extract inhibits CYP2C9. This interaction has not been reported in humans.
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 situation with Opsynvi, which combines macitentan and tadalafil. In lab dish studies, hibiscus appears to block an enzyme called CYP2C9, one of the pathways your body uses to help clear these medicines. If that slowing happened in real life, a bit more of the drug could linger in your system, which could nudge up common side effects like headache, flushing, a stuffy nose, low blood pressure, dizziness, or leg swelling.

The reassuring part: this is only theoretical, seen in test tubes, not in actual people, and it's rated a minor concern. On top of that, hibiscus itself gently lowers blood pressure, so the effects could add together. A cup of hibiscus tea now and then is unlikely to matter, but before using concentrated hibiscus supplements, please check with your pharmacist or doctor.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Johnson SS, Oyelola FT, Ari T, Juho H. In vitro inhibitory activities of the extract of Hibiscus sabdariffa L. (family Malvaceae) on selected cytochrome P450 isoforms. Afr J Tradit Complement Altern Med. 2013 Apr 12;10(3):533-40.
Minor

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

3 of 3

Macitentan, Tadalafil also falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES.

Theoretically, Hibiscus sabdariffa extract might reduce the metabolism of CYP3A4 substrates.
In vitro research shows that Hibiscus sabdariffa calyx extract inhibits CYP3A4. This interaction has not been reported in humans.
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

Opsynvi combines two medicines, macitentan and tadalafil, and both are broken down in your body partly by an enzyme called CYP3A4. In a lab setting, concentrated hibiscus extract seems to slow that enzyme down a bit. If that happened in a real person, these medicines could hang around a little longer than usual, which in theory might nudge up side effects like headache, flushing, low blood pressure, dizziness, stuffy nose, or swelling in the legs.

Here's the reassuring part: this is only a theoretical concern from test-tube work, and it has never actually been reported in people. A cup or two of hibiscus tea is very unlikely to matter. Since hibiscus can also lower blood pressure on its own, just give your pharmacist or doctor a heads-up before using concentrated hibiscus supplements.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Johnson SS, Oyelola FT, Ari T, Juho H. In vitro inhibitory activities of the extract of Hibiscus sabdariffa L. (family Malvaceae) on selected cytochrome P450 isoforms. Afr J Tradit Complement Altern Med. 2013 Apr 12;10(3):533-40.

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

Hibiscus Sabdariffa Also Interacts With Other Medications

Hibiscus Sabdariffa has 2 major, 265 moderate, 821 minor known drug interactions in our database — the Macitentan, Tadalafil one above is among them. If you take anything else, check it against the full list below.

Major 2 Moderate 265 Minor 821 No known interaction 1,742 (incl. Macitentan, Tadalafil)
Taking anything else?

Check Another of Your Medications Against Hibiscus Sabdariffa

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

Everything else you take

See Every Supplement That Interacts With Macitentan, Tadalafil

This page covers Hibiscus Sabdariffa 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

How much people look this up

Where Hibiscus Sabdariffa 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 Hibiscus Sabdariffa
Top half

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

29 days ago today
Medication Macitentan, Tadalafil
Top 25%

#448 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 Hibiscus Sabdariffa

What is Hibiscus Sabdariffa?

Hibiscus Sabdariffa
  • High blood pressure
  • Heart and cholesterol health
  • Digestive upset
  • Antioxidant support
  • Fever and general wellness

Hibiscus sabdariffa is a tart, cranberry-flavored plant most often consumed as a tea, and its best-studied use is for mildly lowering blood pressure. Evidence for other uses is limited, and while hibiscus tea is generally well tolerated in food amounts, concentrated supplements should be used cautiously and avoided in pregnancy. Talk to your pharmacist or doctor before using it for a medical condition.

Read the full Hibiscus Sabdariffa monograph & all interactions
Keep checking

Other Drugs & Hibiscus Sabdariffa

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

2Major
265Moderate
821Minor
1,741No known interaction
2 Major 265 Moderate 821 Minor 1,741 No interaction
Major

2 interactions

Moderate

265 interactions

Showing 60 of 265 moderate interactions — see all 265 on the Hibiscus Sabdariffa page.

Minor

821 interactions

Showing 60 of 821 minor interactions — see all 821 on the Hibiscus Sabdariffa page.

No interaction 1,741 drugs checked — show the list

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

Showing the 60 most looked-up of 1,741 medications checked with no known interaction — see the full Hibiscus Sabdariffa list.

See the full Hibiscus Sabdariffa 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
Hibiscus Sabdariffa 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 Hibiscus Sabdariffa and Macitentan, Tadalafil Together: Common Questions

Can you take Hibiscus Sabdariffa with Macitentan, Tadalafil?
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.
Why are there 3 interactions listed for Hibiscus Sabdariffa and Macitentan, Tadalafil?
Macitentan, Tadalafil belongs to more than one drug category, and Hibiscus Sabdariffa interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Hibiscus Sabdariffa and Macitentan, Tadalafil 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

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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.