Drug & supplement interaction

Nattokinase + Quinapril

Quinapril brand names: Accupril, Accupro.

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

Nattokinase has a moderate interaction with Quinapril. Theoretically, nattokinase might increase the risk of hypotension when used with antihypertensive drugs.

Read the full interaction report
SeverityModerate
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Nattokinase and Quinapril

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

Moderate

ANTIHYPERTENSIVE DRUGS

Why this applies to Quinapril

Quinapril falls under ANTIHYPERTENSIVE DRUGS — the group Nattokinase interacts with.

Theoretically, nattokinase might increase the risk of hypotension when used with antihypertensive drugs.
Some clinical research suggests that nattokinase may reduce systolic and diastolic blood pressure.
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

Here's the simple version. Quinapril already lowers your blood pressure by relaxing your blood vessels. Nattokinase, the natto-derived enzyme, may nudge blood pressure down a little on its own too. Put them together and those two small effects can add up, so in theory your pressure could dip lower than expected.

If that happens, you might feel lightheaded, dizzy, tired, or faint, especially when you stand up quickly. I'll be honest with you though: this concern is mostly theoretical, based on how each one works rather than strong studies. That doesn't mean ignore it. If you're thinking about adding nattokinase, check in with your pharmacist or doctor first, and keep an eye on your blood pressure readings at home.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Kim, J. Y., Gum, S. N., Paik, J. K., Lim, H. H., Kim, K. C., Ogasawara, K., Inoue, K., Park, S., Jang, Y., and Lee, J. H. Effects of nattokinase on blood pressure: a randomized, controlled trial. Hypertens.Res 2008;31(8):1583-1588. PubMed
  2. <p>Maruyama M, Sumi H (eds): Effect of natto diet on blood pressure, in Basic and Clinical Aspects of Japanese Traditional Food Natto II. Japan Technology Transfer Association (JTTAS), 1998, pp 1–3.</p>

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

Nattokinase Also Interacts With Other Medications

Nattokinase has 288 moderate known drug interactions in our database — the Quinapril one above is one of them. If you take anything else, check it against the full list below.

Moderate 288 No known interaction 2,542 (incl. Quinapril)
Taking anything else?

Check Another of Your Medications Against Nattokinase

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

From our Q&A

Questions About Nattokinase or Quinapril

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Nattokinase or Quinapril, 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 Quinapril

This page covers Nattokinase only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Quinapril page lists 166 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), Asarabacca (major) and Siberian Cocklebur (major).

By severity: 6 major · 136 moderate · 24 minor.

From our pharmacist’s overview on the Quinapril page

“Quinapril (Accupril) lowers blood pressure by relaxing blood vessels, and that is where most of the 166 supplements and herbs on this list collide with it. The bulk either push its blood-pressure-lowering effect too far or work against it, and with six entries rated major, this page deserves a careful read, not a skim.”

Reviewed by 2 · Jul 18, 2026

Open the Quinapril interaction page

One more smart check

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

We hold 509 real supplement products containing Nattokinase, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Nattokinase. Your product may carry other ingredients that interact with Quinapril too, on top of Nattokinase — 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 Nattokinase and Quinapril 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 Nattokinase
Top 25%

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

29 days ago today
Medication Quinapril
Steady interest

#2,561 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 Nattokinase

What is Nattokinase?

Nattokinase
  • Heart and circulatory health
  • Blood clot prevention
  • High blood pressure
  • Improving blood flow
  • Cholesterol support

Nattokinase is an enzyme from the fermented soybean food natto that may have mild blood-thinning and blood-flow effects. Some small studies hint at benefits for blood pressure and circulation, but the evidence is limited and more research is needed. Because it can affect clotting, talk to your pharmacist or doctor before trying it, especially if you take medicines or have a bleeding risk.

Read the full Nattokinase monograph & all interactions
Medication

About Quinapril

What Is Quinapril Used For?

Brand names: Accupril, Accupro

Quinapril tablets are used to treat high blood pressure (hypertension). Lowering blood pressure reduces the risk of stroke and heart attack. Quinapril may be used alone or combined with a thiazide diuretic (water pill) when one medication isn't enough.

Quinapril tablets are also used in the management of heart failure as an add-on therapy alongside other standard treatments such as diuretics and/or digitalis.

See full Quinapril drug information
Keep checking

Other Drugs & Nattokinase

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

0Major
288Moderate
0Minor
2,541No known interaction
288 Moderate 2,541 No interaction
Moderate

288 interactions

Showing 60 of 288 moderate interactions — see all 288 on the Nattokinase page.

No interaction 2,541 drugs checked — show the list

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

Showing the 60 most looked-up of 2,541 medications checked with no known interaction — see the full Nattokinase list.

See the full Nattokinase interactions page
See every supplement checked against Quinapril, 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
Nattokinase monograph › Uses, safety, and every drug interaction in one place Quinapril supplement interactions › Every supplement checked against Quinapril, ranked by severity Quinapril drug information › The full plain-English guide to this medication 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 Nattokinase and Quinapril Together: Common Questions

Can you take Nattokinase with Quinapril?
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.
How serious is the Nattokinase and Quinapril 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

Still Have a Question About Quinapril and Nattokinase?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

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.