Drug & supplement interaction

Stevia + Guanethidine Monosulfate

Guanethidine Monosulfate brand names: Ismelin, Isimil.

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

Stevia has a minor interaction with Guanethidine Monosulfate. Theoretically, combining stevia or stevia constituents with antihypertensive agents might increase the risk of hypotension.

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

Stevia and Guanethidine Monosulfate

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

Minor

ANTIHYPERTENSIVE DRUGS

Why this applies to Guanethidine Monosulfate

Guanethidine Monosulfate falls under ANTIHYPERTENSIVE DRUGS — the group Stevia interacts with.

Theoretically, combining stevia or stevia constituents with antihypertensive agents might increase the risk of hypotension.
Stevia extract and stevioside might lower blood pressure in patients with hypertension. However, other clinical research suggests that stevioside does not significantly lower blood pressure in patients with hypertension.
Severity Minor 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

Guanethidine is an older, potent blood pressure medicine that works by lowering the activity of certain nerves, which relaxes your blood vessels. The concern here is simple: some lab and early research hints that concentrated stevia extracts might nudge blood pressure down on their own. If that small effect adds onto guanethidine's already strong lowering, you could in theory dip too low.

To be honest, this is theoretical and rated minor. The human evidence is mixed, and some studies show stevia did nothing to blood pressure. A sprinkle of stevia in your coffee is very unlikely to matter. Still, with a drug this powerful, watch for dizziness, lightheadedness when standing, or feeling faint, and check in with your pharmacist or doctor before starting stevia supplements.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Chan P, Xu DY, Liu JC, et al. The effect of stevioside on blood pressure and plasma catecholamines in spontaneously hypertensive rats. Life Sci 1998;63:1679-84. PubMed
  2. Melis MS. Chronic administration of aqueous extract of Stevia rebaudiana in rats: renal effects. J Ethnopharmacol 1995;47:129-34. PubMed
  3. Melis MS, Sainati AR. Effect of calcium and verapamil on renal function of rats during treatment with stevioside. J Ethnopharmacol 1991;33:257-622. PubMed
  4. Hsieh MH, Chan P, Sue YM, et al. Efficacy and tolerability of oral stevioside in patients with mild essential hypertension: a two-year, randomized, placebo-controlled study. Clin Ther 2003;25:2797-808. PubMed
  5. Chan P, Tomlinson B, Chen YJ, et al. A double-blind placebo-controlled study of the effectiveness and tolerability of oral stevioside in human hypertension. Br J Clin Pharmacol 2000;50:215-20. PubMed
  6. Ferri LA, Alves-Do-Prado W, Yamada SS, et al. Investigation of the antihypertensive effect of oral crude stevioside in patients with mild essential hypertension. Phytother Res 2006;20:732-6. PubMed

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

Stevia Also Interacts With Other Medications

Stevia has 1 moderate, 257 minor known drug interactions in our database — the Guanethidine Monosulfate one above is one of them. If you take anything else, check it against the full list below.

Moderate 1 Minor 257 No known interaction 2,572 (incl. Guanethidine Monosulfate)
Taking anything else?

Check Another of Your Medications Against Stevia

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

Everything else you take

See Every Supplement That Interacts With Guanethidine Monosulfate

This page covers Stevia only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Guanethidine Monosulfate page lists 137 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 · 112 moderate · 21 minor.

From our pharmacist’s overview on the Guanethidine Monosulfate page

“Guanethidine monosulfate (Ismelin) is a forceful older drug for severe high blood pressure, and its interaction list warrants genuine care. Nearly all 137 supplements and herbs on file pull blood pressure one way or the other, either adding to the drug's effect and risking dizziness and faints, or pushing pressure back up and undoing t…”

Reviewed by 2 · Jul 18, 2026

Open the Guanethidine Monosulfate interaction page

One more smart check

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

We hold 1,899 real supplement products containing Stevia, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Stevia. Your product may carry other ingredients that interact with Guanethidine Monosulfate too, on top of Stevia — 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 Stevia and Guanethidine Monosulfate 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 Stevia
Top 10%

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

29 days ago today
Medication Guanethidine Monosulfate
Steady interest

#1,637 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 Stevia

What is Stevia?

  • Sugar substitute / sweetener
  • Blood sugar support in diabetes
  • Weight management
  • Blood pressure support
  • Reducing calorie intake

Stevia is a plant-based, calorie-free sweetener that is widely used as a sugar alternative and is considered safe in normal food amounts by major regulators. Purified stevia extracts have a good safety record, but evidence for medicinal benefits like lowering blood sugar or blood pressure is limited. Talk to your pharmacist or doctor before using stevia supplements for any health condition.

Read the full Stevia monograph & all interactions
Keep checking

Other Drugs & Stevia

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

0Major
1Moderate
257Minor
2,571No known interaction
1 Moderate 257 Minor 2,571 No interaction
Moderate

1 interaction

Minor

257 interactions

Showing 60 of 257 minor interactions — see all 257 on the Stevia page.

No interaction 2,571 drugs checked — show the list

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

Showing the 60 most looked-up of 2,571 medications checked with no known interaction — see the full Stevia list.

See the full Stevia interactions page
See every supplement checked against Guanethidine Monosulfate, 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
Stevia monograph › Uses, safety, and every drug interaction in one place Guanethidine Monosulfate supplement interactions › Every supplement checked against Guanethidine Monosulfate, 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 Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Stevia and Guanethidine Monosulfate Together: Common Questions

Can you take Stevia with Guanethidine Monosulfate?
There is only a minor interaction, which is usually not serious. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Stevia and Guanethidine Monosulfate interaction?
We rate it Minor. This interaction is generally not clinically significant, but it remains worth noting and discussing with your pharmacist.

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

Still Have a Question About Guanethidine Monosulfate and Stevia?

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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.