Drug & supplement interaction

Hawthorn + Nitroglycerin

Nitroglycerin brand names: Nitrostat, Nitrogard SR, Sustachron, Nitro-Bid, Sustachron ER Buccal, and others.

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

Hawthorn has a major interaction with Nitroglycerin. Theoretically, concomitant use might cause additive coronary vasodilatory effects.

Read the full interaction report
SeverityMajor
LikelihoodProbable
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Hawthorn and Nitroglycerin

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

Major

NITRATES

Why this applies to Nitroglycerin

Nitroglycerin falls under NITRATES — the group Hawthorn interacts with.

Theoretically, concomitant use might cause additive coronary vasodilatory effects.
Some evidence shows that hawthorn might lower blood pressure due to vasodilatory effects.
Severity Major Likelihood Probable Evidence D

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..

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the thing with hawthorn and your nitroglycerin. Both of them relax and widen your blood vessels, so taking them together could double up on that effect. Nitroglycerin already drops your blood pressure to ease the workload on your heart, and hawthorn may nudge your blood pressure down a little too. Stacked together, you might feel more lightheaded, dizzy, or even faint, especially when you stand up quickly. Some folks also get a stronger headache or flushing.

I'll be honest, this concern is based on how these two work in theory, not on a pile of human studies, so it isn't a sure thing. Still, since it's flagged as a serious combo, please check with your pharmacist or doctor before adding hawthorn. Don't change your nitroglycerin on your own.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Chang Q, Zuo Z, Harrison F, Chow MS. Hawthorn. J Clin Pharmacol 2002;42:605-12.
  2. Walker AF, Marakis G, Simpson E, et al. Hypotensive effects of hawthorn for patients with diabetes taking prescription drugs: a randomised controlled trial. Br J Gen.Pract 2006;56:437-43.

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

Hawthorn Also Interacts With Other Medications

Hawthorn has 13 major, 177 moderate known drug interactions in our database — the Nitroglycerin one above is one of them. If you take anything else, check it against the full list below.

Major 13 Moderate 177 No known interaction 2,640 (incl. Nitroglycerin)
Taking anything else?

Check Another of Your Medications Against Hawthorn

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

From our Q&A

Questions About Hawthorn or Nitroglycerin

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

This page covers Hawthorn only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Nitroglycerin page lists 26 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Mistletoe (major), Coleus (major), N-acetyl Cysteine (nac) (major) and Beer (moderate).

By severity: 5 major · 11 moderate · 10 minor.

From our pharmacist’s overview on the Nitroglycerin page

“Nitroglycerin (Nitrostat, Nitro-Bid) exists to open blood vessels quickly during angina, so a supplement that also drops blood pressure, or one that fights the drug's effect, is not a small matter, and this list warrants real care before you add to it. The most serious entries pull in two directions.”

Reviewed by 2 · Jul 18, 2026

Open the Nitroglycerin interaction page

One more smart check

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

We hold 2,624 real supplement products containing Hawthorn, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Hawthorn. Your product may carry other ingredients that interact with Nitroglycerin too, on top of Hawthorn — 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 Hawthorn and Nitroglycerin 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 Hawthorn
Top 10%

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

29 days ago today
Medication Nitroglycerin
Top 10%

#208 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 Hawthorn

What is Hawthorn?

Hawthorn
  • Heart failure symptoms
  • High blood pressure
  • Chest pain (angina)
  • Irregular heartbeat
  • Digestive upset
  • Anxiety

Hawthorn is a plant traditionally used for heart-related complaints, and some studies suggest it may modestly help symptoms of mild heart failure when added to standard care. However, the evidence is mixed and it should never replace prescribed heart medicines. Always talk to your pharmacist or doctor before using hawthorn, especially if you have a heart condition.

Read the full Hawthorn monograph & all interactions
Medication

About Nitroglycerin Topical

What Is Nitroglycerin Topical Used For?

Brand names: Nitrostat, Nitrogard SR, Sustachron, Nitro-Bid, Sustachron ER Buccal, Nitroglyn, Nitro Time, Nitrong, Nitrogard, Nitrocine Timecaps, Nitroquick, Rectiv, Gonitro

Rectiv (nitroglycerin ointment 0.4%, applied rectally) is specifically indicated to treat moderate to severe pain associated with chronic anal fissure — a small tear in the lining of the anal canal.

Nitro-Bid (nitroglycerin ointment, applied to the skin) has been used to reduce exercise-related angina (chest pain brought on by physical activity). These are distinct products with separate uses; they are not interchangeable.

See full Nitroglycerin Topical drug information
Keep checking

Other Drugs & Hawthorn

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

13Major
177Moderate
0Minor
2,639No known interaction
13 Major 177 Moderate 2,639 No interaction
Major

13 interactions

Moderate

177 interactions

Showing 60 of 177 moderate interactions — see all 177 on the Hawthorn page.

No interaction 2,639 drugs checked — show the list

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

Showing the 60 most looked-up of 2,639 medications checked with no known interaction — see the full Hawthorn list.

See the full Hawthorn interactions page
See every supplement checked against Nitroglycerin, 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
Hawthorn monograph › Uses, safety, and every drug interaction in one place Nitroglycerin supplement interactions › Every supplement checked against Nitroglycerin, ranked by severity Nitroglycerin Topical 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 Hawthorn and Nitroglycerin Together: Common Questions

Can you take Hawthorn with Nitroglycerin?
This is rated a major interaction, so the combination is best avoided unless your doctor or pharmacist has specifically told you otherwise. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Hawthorn and Nitroglycerin interaction?
We rate it Major. This is a clinically significant combination that is generally best avoided, or used only under the direct supervision of your physician or pharmacist.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Nitroglycerin and Hawthorn?

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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.