Drug & supplement interaction

Cowhage + Guanethidine Monosulfate

Guanethidine Monosulfate brand names: Ismelin, Isimil.

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

Cowhage has a moderate interaction with Guanethidine Monosulfate. Theoretically, concomitant use of cowhage and guanethidine might increase the risk of hypotension.

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

Cowhage and Guanethidine Monosulfate

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

Moderate

GUANETHIDINE (Ismelin)

Theoretically, concomitant use of cowhage and guanethidine might increase the risk of hypotension.
Cowhage contains levodopa. Use of levodopa with guanethidine might cause additive hypotension; avoid using.
Severity Moderate 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 to know if you're taking guanethidine (Ismelin), which is an older blood pressure medication that works by lowering the activity of your sympathetic nervous system. Cowhage naturally contains L-dopa, the same active compound found in some Parkinson's drugs, and L-dopa can lower blood pressure on its own. Stacking the two together could push your blood pressure down more than expected.

In real life, that might show up as dizziness, lightheadedness, feeling faint when you stand up, or even a fall. I'll be honest: this is a theoretical concern based on how the two work, not hard clinical proof, so don't panic. But because both can drop your pressure, it's worth a quick chat with your doctor or pharmacist before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
  2. HP-200 in Parkinson's Disease study group. An alternative medicine treatment for Parkinson's disease: Results of a multicenter clinical trial. J Alt Comp Med 1995;1:249-55. DOI
  3. Vadivel V, Janardhanan K. Nutritional and anti-nutritional composition of velvet bean: an under-utilized food legume in south India. Int J Food Sci Nutr 2000;51:279-87. PubMed
  4. Prakash, D., Niranjan, A., and Tewari, S. K. Some nutritional properties of the seeds of three Mucuna species. Int.J.Food Sci.Nutr. 2001;52(1):79-82.
  5. Vadivel, V. and Janardhanan, K. Nutritional and antinutritional characteristics of seven South Indian wild legumes. Plant Foods Hum.Nutr 2005;60(2):69-75. PubMed
  6. Creapure (Creatine Monohydrate). Toxicological Datasheet. Degussa BioActives. Available at: https://www.fda.gov/ohrms/DOCKETS/.../95s-0316-rpt0154-54-Ref-50-vol112.pdf.
  7. Pulikkalpura H, Kurup R, Mathew PJ, Baby S. Levodopa in Mucuna pruriens and its degradation. Sci Rep 2015;5:11078. 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

Cowhage Also Interacts With Other Medications

Cowhage has 17 major, 175 moderate 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.

Major 17 Moderate 175 No known interaction 2,638 (incl. Guanethidine Monosulfate)
Taking anything else?

Check Another of Your Medications Against Cowhage

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

Everything else you take

See Every Supplement That Interacts With Guanethidine Monosulfate

This page covers Cowhage 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 Cowhage as Part of a Dietary Supplement Product? Check It for Interactions

We hold 1,218 real supplement products containing Cowhage, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Cowhage. Your product may carry other ingredients that interact with Guanethidine Monosulfate too, on top of Cowhage — 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 Cowhage 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 Cowhage
Top 10%

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

29 days ago today
Medication Guanethidine Monosulfate
Top 25%

#697 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 Cowhage

What is Cowhage?

  • Parkinson's disease symptoms
  • Male fertility and libido
  • Mood and stress support
  • Traditional aphrodisiac
  • General energy and vitality

Cowhage (Mucuna pruriens) is a tropical legume best known as a natural source of L-dopa, the compound the body turns into dopamine. It is most studied for Parkinson's disease symptoms and male fertility, but evidence is still limited and the L-dopa content makes it potentially powerful and risky—talk to your doctor or pharmacist before using it.

Read the full Cowhage monograph & all interactions
Keep checking

Other Drugs & Cowhage

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

17Major
175Moderate
0Minor
2,637No known interaction
17 Major 175 Moderate 2,637 No interaction
Major

17 interactions

Moderate

175 interactions

Showing 60 of 175 moderate interactions — see all 175 on the Cowhage page.

No interaction 2,637 drugs checked — show the list

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

Showing the 60 most looked-up of 2,637 medications checked with no known interaction — see the full Cowhage list.

See the full Cowhage 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
Cowhage 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 Cowhage and Guanethidine Monosulfate Together: Common Questions

Can you take Cowhage with Guanethidine Monosulfate?
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 Cowhage and Guanethidine Monosulfate 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 Guanethidine Monosulfate and Cowhage?

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.