Drug & supplement interaction

Isopropylnorsynephrine + Hydralazine

Hydralazine brand names: Apresoline, Hylazin, Hydralazine, Dralzine, Apresoline Injection.

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

Isopropylnorsynephrine has a moderate interaction with Hydralazine. Theoretically, isopropylnorsynephrine might decrease the effects of 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

Isopropylnorsynephrine and Hydralazine

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

Moderate

ANTIHYPERTENSIVE DRUGS

Why this applies to Hydralazine

Hydralazine falls under ANTIHYPERTENSIVE DRUGS — the group Isopropylnorsynephrine interacts with.

Theoretically, isopropylnorsynephrine might decrease the effects of antihypertensive drugs.
In vitro research shows that isopropylnorsynephrine is a highly selective, direct-acting beta-adrenergic receptor agonist with positive chronotropic effects, and hypertension has been reported in patients taking combination products containing isopropylnorsynephrine and other stimulants.
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 basic tension at play. You take hydralazine to relax your blood vessels and bring your blood pressure down. Isopropylnorsynephrine is a stimulant that does the opposite kind of thing, it switches on receptors that can speed up your heart and nudge blood pressure up. So in theory the supplement could push against the work hydralazine is doing, making your treatment less effective. Hydralazine is not a prodrug here, so there's no flip in direction to worry about.

I'll be honest, this concern comes mostly from lab studies, not strong human trials, so think of it as a reasonable caution rather than a proven problem. Still, since hydralazine can already cause a fast heartbeat and flushing, adding a stimulant may amplify that. Please check with your pharmacist or doctor before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Venhuis B, Keizers P, van Riel A, de Kaste D. A cocktail of synthetic stimulants found in a dietary supplement associated with serious adverse events. Drug Test Anal. 2014 Jun;6(6):578-81. doi: 10.1002/dta.1664. Epub 2014 May 6. PubMed
  2. Anderson WG. The sympathomimetic activity of N-isopropyloctopamine in vitro. J Pharmacol Exp Ther 1983;225(3):553-8. DOI

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

Isopropylnorsynephrine Also Interacts With Other Medications

Isopropylnorsynephrine has 343 moderate known drug interactions in our database — the Hydralazine one above is one of them. If you take anything else, check it against the full list below.

Moderate 343 No known interaction 2,487 (incl. Hydralazine)
Taking anything else?

Check Another of Your Medications Against Isopropylnorsynephrine

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

From our Q&A

Questions About Isopropylnorsynephrine or Hydralazine

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

This page covers Isopropylnorsynephrine only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Hydralazine page lists 136 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), Tyramine (major) and Adrafinil (moderate).

By severity: 4 major · 111 moderate · 21 minor.

From our pharmacist’s overview on the Hydralazine page

“Hydralazine is the drug doctors reach for when blood pressure needs forcing down, so I read this list of 136 supplement interactions with genuine concern rather than routine caution. Start with the four rated major: two are toxic plants with direct effects on the heart and blood vessels, tyramine can push pressure back up and undo the…”

Reviewed by 2 · Jul 18, 2026

Open the Hydralazine interaction page

One more smart check

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

We hold 48 real supplement products containing Isopropylnorsynephrine, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Isopropylnorsynephrine. Your product may carry other ingredients that interact with Hydralazine too, on top of Isopropylnorsynephrine — 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 Isopropylnorsynephrine and Hydralazine 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 Isopropylnorsynephrine
Steady interest

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

29 days ago today
Medication Hydralazine
Top 25%

#575 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 Isopropylnorsynephrine

What is Isopropylnorsynephrine?

  • Weight loss and fat burning
  • Pre-workout energy and stimulation
  • Topical fat reduction (creams and gels)
  • Appetite suppression
  • Athletic performance

Isopropylnorsynephrine is a synthetic stimulant chemically related to synephrine, marketed mainly in weight-loss and pre-workout supplements. It has very little human safety or effectiveness research, and as a stimulant it may raise heart rate and blood pressure, so caution is strongly advised. Talk with a pharmacist or doctor before using any product that contains it.

Read the full Isopropylnorsynephrine monograph & all interactions
Medication

About Hydralazine

What Is Hydralazine Used For?

Brand names: Apresoline, Hylazin, Hydralazine, Dralzine, Apresoline Injection

Hydralazine tablets are used to treat essential hypertension (high blood pressure), either alone or alongside other blood pressure medications.

The hydrALAZINE Hydrochloride injection form is used in hospital settings for severe essential hypertension when oral medication cannot be taken or when blood pressure needs to be lowered urgently.

See full Hydralazine drug information
Keep checking

Other Drugs & Isopropylnorsynephrine

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

0Major
343Moderate
0Minor
2,486No known interaction
343 Moderate 2,486 No interaction
Moderate

343 interactions

Showing 60 of 343 moderate interactions — see all 343 on the Isopropylnorsynephrine page.

No interaction 2,486 drugs checked — show the list

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

Showing the 60 most looked-up of 2,486 medications checked with no known interaction — see the full Isopropylnorsynephrine list.

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

Can you take Isopropylnorsynephrine with Hydralazine?
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 Isopropylnorsynephrine and Hydralazine 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 Hydralazine and Isopropylnorsynephrine?

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.