Herb & supplement monograph

Quassia Drug Interactions, Uses, Effectiveness, Safety & More

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS ·Updated July 2026

What is this page for?

First and foremost: how Quassia interacts with medications. The heart of this page is the interaction list — every drug Quassia is known to interact with, and how serious each one is.

But these pages have grown well beyond that into a full monograph — what Quassia is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy

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Reviewed by licensed pharmacists Sourced from Natural Medicines

On this page

Quassia Drug Interactions: The Bottom Line

From the HelloPharmacist Editorial Team · Updated July 2026

Based on the available evidence, the overall risk of a clinically significant Quassia drug interaction appears low for most people, since none of the reported interactions are well documented in humans. No interactions are rated major, and while most carry a moderate rating, every one rests on animal, lab, or theoretical evidence rather than proven human effects.

Interactions deserving the most attention

The combinations worth the closest watch involve medicines where even a small shift matters. Animal research suggests quassia may lower blood sugar, so people taking diabetes medications could face a higher chance of low blood sugar and should keep an eye on their glucose readings. Quassia might also add to the effects of digoxin, a heart medicine with a narrow safety margin, and heavy use could worsen potassium loss in people on potassium-depleting diuretics.

What the rest of the list means

A long list of interacting medications does not mean each combination is harmful. Most entries here are theoretical, and none have been confirmed in human studies. For example, because quassia is thought to raise stomach acid, it is flagged with acid-reducing medicines like antacids, H2-blockers, and PPIs, but only as a possible drop in their effectiveness, not a safety risk.

Check your medications against Quassia

Based on HelloPharmacist’s Quassia interaction data and reviewed under our editorial standards.

Interaction report

Drugs that interact with Quassia

198 medications have a known interaction with Quassia, graded by severity. Select any drug for the full evidence-based detail.

Don’t want to scroll the list? Just ask.

Tell us the medications you take and we’ll check each one against Quassia using our pharmacist-reviewed interaction data.

AI summaries are generated from our Quassia interaction data for education only — always confirm with your pharmacist. How we use AI

2,830 drugs

Read The List Like a Pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
Probable. Interaction 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.
Possible. 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
Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
Each drug listed above links to the full report for that exact Quassia combination — clinical detail, likelihood, evidence level, and citations.
Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

The big picture

The kinds of drugs Quassia affects

Every type of medication (drug category) Quassia is known to interact with. Open any category for the detail — or search your exact drug in the checker above.

All 6 drug categories Quassia interacts with

Antidiabetes DrugsDigoxin (lanoxin)Diuretic DrugsAntacidsH2-blockersProton Pump Inhibitors (ppis)

Antidiabetes Drugs

In animals, quassia extract reduced levels of fasting glucose. Theoretically, quassia might have additive effects when used with antidiabetes drugs. This might increase the risk of hypoglycemia in some patients. Monitor blood glucose levels closely.
Some antidiabetes drugs include glimepiride (Amaryl), glyburide (DiaBeta, Glynase PresTab, Micronase), insulin, metformin (Glucophage), pioglitazone (Actos), rosiglitazone (Avandia), and others.