Drug & supplement interaction

Quassia + Amlodipine Besylate

Amlodipine Besylate brand name: Norvasc.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 13, 2026
The bottom line No known interaction

We found no known interaction between Quassia and Amlodipine Besylate 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.

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Interaction report

Quassia and Amlodipine Besylate

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 Amlodipine Besylate and Quassia 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.

Quassia safety at a glance

Quassia overall Use caution Likely fine in small amounts used in foods, but larger or long-term doses may irritate the digestive tract.
Pregnancy Likely Unsafe When used orally; avoid using. Quassia has cytotoxic and emetic properties. There is insufficient reliable information available about the safety of rectal or t... Read the full pregnancy detail
Breastfeeding Likely Unsafe When used orally; avoid using. Quassia has cytotoxic and emetic properties. There is insufficient reliable information available about the safety of rectal or t... 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 Amlodipine Besylate and Quassia? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Amlodipine Besylate

Interactions in our licensed database are recorded against drug classes, not just single drug names. Amlodipine Besylate is filed under 5 classifications — including calcium channel blockers, antihypertensive drugs, cytochrome p450 3a4 (cyp3a4) substrates. Quassia has documented interactions with 6 drug classes — the most serious being antidiabetes drugs (moderate), digoxin (lanoxin) (moderate) and diuretic drugs (moderate) — and none of Amlodipine Besylate’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

Quassia Does Interact With Other Medications

Quassia has 162 moderate, 36 minor known drug interactions in our database — Amlodipine Besylate isn’t one of them. If you take anything else, check it against the full list below.

Moderate 162 Minor 36 No known interaction 2,632 (incl. Amlodipine Besylate)
Taking anything else?

Check Another of Your Medications Against Quassia

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

What to actually watch for

What Quassia Itself Has Been Linked To

This is not an interaction — nothing below involves Amlodipine Besylate. It is the side-effect record for Quassia on its own, from the licensed Natural Medicines monograph. If something new turns up after you add Quassia, this list is the first place to look. One entry is worth acting on rather than waiting out — marked below.

  • Loss of vision Worth acting on Additional detail

    “Orally, quassia can cause mucous membrane irritation, nausea, and vomiting when used in medicinal amounts (4,18). Long-term use can cause vision changes and blindness (18).

    Topically, quassia seems to be well tolerated. No adverse effects have been reported.”

    Quassia · Natural Medicines adverse-effect record, reported in nausea and vomiting.

    3 sources cited
    1. 4. Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.
    2. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
    3. 99995. Ferrari A, Diehl C. Evaluation of the efficacy and tolerance of a topical gel with 4% quassia extract in the treatment of rosacea. J Clin Pharmacol. 2012;52(1):84-8. PubMed
  • Blurred vision Additional detail

    Recorded for Quassia in the same Natural Medicines adverse-effect record shown under Loss of vision above.

  • Vomiting / Nausea Additional detail

    “Orally, quassia has been reported to cause mucous membrane irritation, nausea, and vomiting when used in medicinal amounts (4,18).”

    Quassia · Natural Medicines adverse-effect record, reported in nausea and vomiting.

    2 sources cited
    1. 4. Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.
    2. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.

Everything above comes from the Natural Medicines adverse-effect record for Quassia — expand a row for the licensed statement it rests on. We haven’t matched Amlodipine Besylate to its FDA label in our system yet, so we can’t compare its own side-effect list here — the leaflet that comes with your prescription is the authoritative list for Amlodipine Besylate.

Special populations

Quassia in Pregnancy & Breastfeeding

Pregnancy And Lactation Likely Unsafe

When used orally; avoid using. Quassia has cytotoxic and emetic properties. There is insufficient reliable information available about the safety of rectal or topical use during pregnancy or lactation; avoid using.

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

From our Q&A

Questions About Quassia or Amlodipine Besylate

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Quassia or Amlodipine Besylate, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Amlodipine Besylate

This page covers Quassia only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Amlodipine Besylate page lists 232 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), Coleus (major) and Grapefruit (major).

Open the Amlodipine Besylate interaction page

One more smart check

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

We hold 172 real supplement products containing Quassia, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Quassia. Even though Quassia itself has no known interaction with Amlodipine Besylate, 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 Quassia and Amlodipine Besylate 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 Quassia
Steady interest

#1,051 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Amlodipine Besylate
Top 5%

#42 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 Quassia reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Quassia and Amlodipine Besylate 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 Quassia

What is Quassia?

  • Loss of appetite
  • Digestive upset
  • Head lice (topical)
  • Intestinal worms/parasites
  • Bitter tonic

Quassia is a tropical wood known for its very bitter taste, traditionally used as a digestive bitter and as a folk remedy for parasites and head lice. Human evidence for these uses is limited, and high doses may irritate the stomach, so it should be used cautiously and avoided in pregnancy.

Quassia amara · Simaroubaceae · Wood (bark and stem wood) · Dried wood chips, tea/infusion, liquid extract, tincture, capsules, and topical lotions

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

Quassia: dosing

There is no well-established, standardized dose for quassia. Traditional preparations include a bitter tea made from a small amount of wood chips, as well as tinctures and capsules.Because the strength of products varies and reliable dosing studies are lacking, follow the directions on the product label and use the lowest amount that works. Avoid large or long-term doses.

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

Read the full Quassia monograph & all interactions
Medication

About Amlodipine

What Is Amlodipine Used For?

Brand name: Norvasc

Amlodipine treats high blood pressure (hypertension) in adults and children aged 6–17 years. Lowering blood pressure reduces the risk of strokes and heart attacks. Sdamlo (oral solution) is specifically indicated for hypertension in adults and pediatric patients 6 years of age and older.

Amlodipine also treats coronary artery disease in adults, including chronic stable angina (chest pain with exertion), vasospastic angina (Prinzmetal's or variant angina, caused by coronary artery spasms), and documented coronary artery disease in patients without heart failure or significantly reduced heart pumping function.

Most-Reported Side Effects for Amlodipine Besylate

From FAERS, the FDA’s public side-effect reporting system (168,900 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Fatigue 10,835 reports
Nausea 9,443 reports
Diarrhea 8,945 reports
Dyspnea 8,684 reports
Dizziness 7,742 reports
See full Amlodipine drug information
Keep checking

Other Drugs & Quassia

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

0Major
162Moderate
36Minor
2,631No known interaction
162 Moderate 36 Minor 2,631 No interaction
Moderate

162 interactions

Showing 60 of 162 moderate interactions — see all 162 on the Quassia page.

Minor

36 interactions

No interaction 2,631 drugs checked — show the list

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

Showing the 60 most looked-up of 2,631 medications checked with no known interaction — see the full Quassia list.

See the full Quassia interactions page
See every supplement checked against Amlodipine Besylate, ranked by severity
Evidence & sources

Quassia References

The 8 references that drive our Quassia 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. Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.
  2. Robbers JE, Speedie MK, Tyler VE. Pharmacognosy and Pharmacobiotechnology. Baltimore, MD: Williams & Wilkins, 1996.
  3. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
  4. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
  5. Jensen O, Nielsen AO, Bjerregaard P. Pediculosis capitis treated with quassia tincture. Acta Derm Venereol 1978;58:557-9. DOI
  6. Diehl C, Ferrari A. Efficacy of topical 4% Quassia amara gel in facial seborrheic dermatitis:a randomized, double-blind, comparative study. J Drugs Dermatol. 2013;12(3):312-5.
  7. Ferrari A, Diehl C. Evaluation of the efficacy and tolerance of a topical gel with 4% quassia extract in the treatment of rosacea. J Clin Pharmacol. 2012;52(1):84-8. PubMed
  8. Husain GM, Singh PN, Singh RK, Kumar V. Antidiabetic activity of standardized extract of Quassia amara in nicotinamide-streptozotocin-induced diabetic rats. Phytother Res. 2011;25(12):1806-12.

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 Quassia and Amlodipine Besylate Together: Common Questions

Is it safe to take Quassia with Amlodipine Besylate?
We do not list a known interaction between Quassia and Amlodipine Besylate. 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.
How was the Quassia and Amlodipine Besylate combination checked?
Interactions in our licensed database are recorded against drug classes. Amlodipine Besylate is filed under 5 classifications, and Quassia has documented interactions with 6 drug classes — none of Amlodipine Besylate'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 Quassia interact with any other medications?
Yes. Quassia has 198 documented drug interactions in our database — Amlodipine Besylate 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 Amlodipine Besylate interact with any supplements?
Yes. Amlodipine Besylate has documented interactions with 232 supplements in our database — Quassia is not one of them. The Amlodipine Besylate 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

Quassia monograph Uses, safety profile, and every drug interaction in one place Amlodipine drug information The full plain-English guide to this medication Amlodipine Besylate supplement interactions Every supplement checked against Amlodipine Besylate, 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 8 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Amlodipine Besylate and Quassia?

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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.