Medication interaction hub

What Supplements Interact with Guanethidine Monosulfate?

Guanethidine Monosulfate brand names: Ismelin, Isimil. Every interaction below applies to the brands too.

137 Interactions 4 Major 112 Moderate 21 Minor
Curated & coded by · Clinical Pharmacist · Updated September 27, 2026

Drug–supplement interaction data sourced from Natural Medicines Pro, the licensed clinical database from TRC Healthcare / Therapeutic Research, with additional analysis by the HelloPharmacist Pharmacist Team. Our sources · Editorial policy

What is this page for?

One answer, for one medication: what supplements and herbal products interact with Guanethidine Monosulfate? Every vitamin, herb, and supplement ingredient we’ve checked against it is on this page, ranked by severity, each linking to the full report for that exact pair.

This page covers supplement interactions only — to check Guanethidine Monosulfate against your other medications, use the drug–drug interaction checker. Educational information from our licensed clinical databases, not medical advice. Our editorial policy

HelloPharmacist Bottom Line
Our Pharmacist Explains
What is this? The interaction data in the HelloPharmacist supplement database is licensed from Natural Medicines Pro by TRC Healthcare (Therapeutic Research). HelloPharmacist pharmacists often add our own analysis and context on top of that licensed data — such as this Bottom Line summary and the notes on individual interaction pages — and any such commentary is noted as ours.

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 treatment. Tyramine, abundant in aged cheeses and fermented foods, is one of the four major-rated entries for exactly that second reason.

Activated charcoal is another of the four majors; it soaks up the dose in the gut before it can absorb, and seventeen entries in all interfere with oral absorption this way, so space them well apart from the pill. Most of the 112 moderate entries add to the drug's pressure-lowering effect, and fish oil, one of the most widely taken supplements there is, sits among them.

— , Clinical Pharmacist · July 18, 2026

Major 4 Moderate 112 Minor 21 No known interaction 1,315

This box checks one ingredient at a time (like turmeric or magnesium). Taking a supplement product with a whole label of ingredients? Search the product instead — we check every ingredient on it ↓

Top Ingredient Interactions

Guanethidine Monosulfate: Top Interactions at a Glance

The most significant Guanethidine Monosulfate supplement & herbal interactions, colored by severity. Tap any ingredient to open the full report for that pair.

Showing the 12 highest-ranked of 137 interacting ingredients — plus 1,315 more checked with no known interaction. See the complete ranked list.

Start here

The Major Interactions to Know About

The most clinically significant Guanethidine Monosulfate + supplement combinations in our database, best-documented first. Open any card for the full report.

Major Likelihood Likely American Hellebore + Guanethidine Monosulfatei

American hellebore can have potent cardiovascular effects due to the toxic steroid ester alkaloids it contains.

Read the full interaction Major Likelihood Likely Tyramine + Guanethidine Monosulfatei

Tyramine may increase the risk of hypertension and reduce the effects of antihypertensive drugs.

Read the full interaction Major Likelihood Probable Activated Charcoal + Guanethidine Monosulfatei

Activated charcoal reduces systemic exposure to many drugs, including those that undergo enterohepatic recirculation, regardless of the route of administration.

Read the full interaction Major Likelihood Probable American Mistletoe + Guanethidine Monosulfatei

American mistletoe contains phoratoxin, a compound toxic to humans that induces smooth muscle contraction and vasoconstriction, potentially increasing blood pre...

Read the full interaction
The complete list

Every Supplement Checked Against Guanethidine Monosulfate

All 1,452 ingredients in our database, ranked by severity — 137 with a Guanethidine Monosulfate interaction on file and 1,315 with none found. Filter by severity or search any ingredient; hover the for what each ingredient is.

Looking for an interaction with a specific supplement product? Search products instead ↓

Straight answers

Can You Take It With Guanethidine Monosulfate?

One-line answers, one card per combination — scroll through today’s 20 and tap any card for the full report. A different set rotates in daily until every combination has had its turn.

Can you take Ash with Guanethidine Monosulfate?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, concomitant use of ash seed with antihypertensive drugs might have additive blood pressure lowering effects.

Full Ash + Guanethidine Monosulfate answer

Can you take Ashwagandha with Guanethidine Monosulfate?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, taking ashwagandha with antihypertensive drugs might increase the risk of hypotension.

Full Ashwagandha + Guanethidine Monosulfate answer

Can you take Baikal Skullcap with Guanethidine Monosulfate?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, concomitant use of Baikal skullcap with antihypertensive drugs might have additive effects and increase the risk of hypotensi...

Full Baikal Skullcap + Guanethidine Monosulfate answer

Can you take Basil with Guanethidine Monosulfate?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, basil might increase the risk of hypotension when taken with antihypertensive drugs.

Full Basil + Guanethidine Monosulfate answer

Can you take Berberine with Guanethidine Monosulfate?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, berberine might have additive effects with antihypertensive drugs.

Full Berberine + Guanethidine Monosulfate answer

Can you take Beta-glucans with Guanethidine Monosulfate?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, taking beta-glucans with antihypertensive drugs might increase the risk of hypotension.

Full Beta-glucans + Guanethidine Monosulfate answer

Can you take Betony with Guanethidine Monosulfate?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, betony might have additive effects with blood pressure lowering drugs due to hypotensive activity of the glycosides found in...

Full Betony + Guanethidine Monosulfate answer

Can you take Black Seed with Guanethidine Monosulfate?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, taking black seed with antihypertensive drugs might increase the risk of hypotension.

Full Black Seed + Guanethidine Monosulfate answer

Can you take Blue Cohosh with Guanethidine Monosulfate?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Constituents in blue cohosh might increase blood pressure by causing coronary vasoconstriction.

Full Blue Cohosh + Guanethidine Monosulfate answer

Can you take Breadfruit with Guanethidine Monosulfate?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, concomitant use with antihypertensive drugs might increase the risk of hypotension.

Full Breadfruit + Guanethidine Monosulfate answer

Can you take Bridelia with Guanethidine Monosulfate?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Animal research suggests that Bridelia extracts decrease arterial pressure.

Full Bridelia + Guanethidine Monosulfate answer

Can you take Calamus with Guanethidine Monosulfate?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, taking calamus with other antihypertensive medications might increase the risk of hypotension.

Full Calamus + Guanethidine Monosulfate answer

Can you take Cannabigerol (cbg) with Guanethidine Monosulfate?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, taking cannabigerol with antihypertensive drugs might increase the risk of hypotension.

Full Cannabigerol (cbg) + Guanethidine Monosulfate answer

Can you take Caprylic Acid with Guanethidine Monosulfate?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, caprylic acid might increase the risk of hypotension when used with antihypertensive drugs.

Full Caprylic Acid + Guanethidine Monosulfate answer

Can you take Catechu with Guanethidine Monosulfate?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, concomitant use with antihypertensive drugs might increase the risk of hypotension.

Full Catechu + Guanethidine Monosulfate answer

Can you take Ceylon Cinnamon with Guanethidine Monosulfate?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, Ceylon cinnamon might have additive effects with antihypertensive drugs and increase the risk of hypotension.

Full Ceylon Cinnamon + Guanethidine Monosulfate answer

Can you take Cocoa with Guanethidine Monosulfate?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, taking cocoa with antihypertensive drugs might increase the risk of hypotension.

Full Cocoa + Guanethidine Monosulfate answer

Can you take Coconut Water with Guanethidine Monosulfate?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, taking coconut water with antihypertensive drugs might increase the risk of hypotension.

Full Coconut Water + Guanethidine Monosulfate answer

Can you take Coleus with Guanethidine Monosulfate?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, combining coleus with antihypertensive drugs might cause additive blood pressure lowering effects and increase the risk of hy...

Full Coleus + Guanethidine Monosulfate answer

Can you take Coltsfoot with Guanethidine Monosulfate?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, excessive doses of coltsfoot may interfere with antihypertensive or cardiovascular therapy.

Full Coltsfoot + Guanethidine Monosulfate answer
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 entry links to a full report with the clinical detail, likelihood, evidence level, and citations for that exact combination.
  • Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

How Does Our Interaction Checker Work?

Behind every verdict on this page is a category system. Our source database doesn’t document supplement interactions drug-by-drug — it documents them against groups of medications that behave the same way (for example, “drugs processed by the CYP3A4 liver enzyme” or “blood-thinning medications”).

So the check works in three steps: (1) Guanethidine Monosulfate is classified into the pharmacology categories it belongs to, (2) every supplement interaction documented against any of those categories is inherited by Guanethidine Monosulfate, and (3) each ingredient keeps its own severity, likelihood, and evidence grades from the underlying record. That’s why one supplement can carry several records for one drug — it may interact through more than one category.

Guanethidine Monosulfate sits in 3 interaction categories. Open any one to see what the group means:

Antihypertensive Drugs 119 ingredients

Blood-pressure-lowering medications. Supplements that lower (or raise) blood pressure can amplify or fight these drugs.

119 of the supplement ingredients on this page reach Guanethidine Monosulfate through this category.

Oral Drugs 17 ingredients

A pharmacology grouping from our source database: medications in this group share a property that certain supplements are known to interact with, so an interaction documented for the group applies to every drug in it.

17 of the supplement ingredients on this page reach Guanethidine Monosulfate through this category.

Guanethidine (Ismelin) 1 ingredient

A pharmacology grouping from our source database: medications in this group share a property that certain supplements are known to interact with, so an interaction documented for the group applies to every drug in it.

1 of the supplement ingredient on this page reaches Guanethidine Monosulfate through this category.

Related: does Guanethidine Monosulfate deplete any nutrients?

Guanethidine Monosulfate has 2 reported nutrient associations in the research literature — see the Guanethidine Monosulfate nutrient depletion report.

Check a real product

Take a Supplement Product? Check the Whole Bottle Against Guanethidine Monosulfate

Most supplements are combination products — and the interaction may come from an ingredient you didn’t buy it for. Search any product below (or scan its label) and we’ll check every ingredient on it against Guanethidine Monosulfate.

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Products that contain Guanethidine Monosulfate-interacting ingredients

Real supplements from the NIH label database that contain the top interacting ingredients on this page — each one is worth a full label check before combining with Guanethidine Monosulfate.

TNT Thermanite by GEC Genetic Edge Compounds contains Tyramine Diablos ECA Fire Caps by Innovative Laboratories contains Tyramine Ultimate Burn by Schwartz Laboratories contains Tyramine Final Cutz by Infinite Labs contains Tyramine
Pharmacist Counseling Corner

Guanethidine Monosulfate & Supplements: Common Questions

What supplements interact with Guanethidine Monosulfate?
More than you might expect — 137 in total, though they are far from equal: 4 are rated major, 112 moderate, and 21 minor. The ranked list on this page puts the ones that genuinely matter first, and every entry opens a full report on that exact pair. The highest-ranked right now: American Hellebore, Tyramine, Activated Charcoal.
Which Guanethidine Monosulfate supplement interactions are the most serious?
The 4 major-rated combinations — led by American Hellebore, Tyramine, Activated Charcoal and American Mistletoe — deserve real caution: these are the ones generally best avoided, or used only with your prescriber watching. If you take any of them today, don't panic and don't stop anything abruptly — call your pharmacist first. Jump to the ranked list.
Can I take vitamins or supplements while on Guanethidine Monosulfate?
Usually yes — most people on Guanethidine Monosulfate can take most supplements. The catch is the exceptions, and they aren't always the exotic ones (St. John's Wort trips up more prescriptions than almost anything sold next to it). Look up each ingredient you actually take in the list above, and treat "no known interaction" as a green-ish light, not a guarantee. Try the label scanner or the interaction checker.
Do brands like Ismelin have the same supplement interactions as Guanethidine Monosulfate?
Yes — Ismelin, Isimil all contain Guanethidine Monosulfate, so everything on this page applies to them equally. Interactions belong to the active drug, never to the brand on the box; the same is true of generics.
Where do these interaction ratings come from?
Every rating comes from the Natural Medicines database — the same evidence-graded reference pharmacists and hospitals use — and each interaction carries three separate grades: severity (how bad it can be), likelihood (how well it's documented in studies and case reports), and an evidence level. Our pharmacists review the content; we never let an AI decide an interaction. See how to read the ratings and our editorial policy.
Does Guanethidine Monosulfate deplete any vitamins or nutrients?
It might — Guanethidine Monosulfate has 2 reported nutrient-depletion associations in the research literature, which is a different question from interactions: instead of a supplement changing the drug, the drug may lower a nutrient over time. See the Guanethidine Monosulfate nutrient depletion report for the specifics and what to discuss with your pharmacist.
What about Guanethidine Monosulfate and my other medications?
This page covers Guanethidine Monosulfate against supplements and herbal ingredients. Checking Guanethidine Monosulfate against your other prescription or OTC medications is a different tool — our drug interaction checker covers that side. Head to the drug–drug interaction checker.

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

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Sourcing

Where This Data Comes From — and Why You Can Trust It

🧪 Licensed clinical database

Every interaction verdict on this page comes from Natural Medicines Pro (TRC Healthcare / Therapeutic Research) — the same evidence-graded reference used by pharmacists and hospitals. We license this data directly; we do not scrape it, and no AI invents an interaction.

🧑‍⚕️ Pharmacist review

This page is curated and coded by , Clinical Pharmacist, with additional analysis by the HelloPharmacist Pharmacist Team. Editorial commentary is ours; the licensed interaction records are shown as sourced.

🔄 Kept current

Our interaction database refreshes on a weekly cycle, and this page re-checks the live database every time it’s rebuilt — what you see reflects the database as of September 27, 2026.

🔍 Full transparency

How every dataset on this site is sourced, licensed, and updated is documented publicly: our data sources · editorial policy · how we use AI.

Educational information, not medical advice. An interaction being on file does not mean it will happen to you — and absence of one is not proof of safety. Never start or stop a medication or supplement without talking to your pharmacist or doctor.