Drug & supplement interaction

Beer + Guanethidine Monosulfate

Guanethidine Monosulfate brand names: Ismelin, Isimil.

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

Beer has a moderate interaction with Guanethidine Monosulfate. Theoretically, concomitant use may interfere with blood pressure control.

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

Beer and Guanethidine Monosulfate

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

Moderate

ANTIHYPERTENSIVE DRUGS

Why this applies to Guanethidine Monosulfate

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

Theoretically, concomitant use may interfere with blood pressure control.
Clinical research suggests that consumption of alcohol can increase both systolic and diastolic blood pressure. However, acute alcohol intoxication can also increase the risk of hypotension and additive effects with antihypertensive drugs.
Severity Moderate Likelihood Probable Evidence B

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

Guanethidine is an older, powerful blood pressure medicine that works by lowering the activity of certain nerves, so it can already drop your blood pressure quite a bit, especially when you stand up. Adding beer can pull in two directions. Over time, regular drinking can actually push blood pressure up and work against your medicine. But a drink or two in the moment tends to relax and widen your blood vessels, which can stack on top of guanethidine's effect.

That combination can leave you feeling dizzy, lightheaded, or faint, particularly when you rise from sitting or lying down. Guanethidine is not a prodrug, so this is about added effects, not changed activation. The evidence here is moderate. Please check with your pharmacist or doctor before drinking on this medication.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Fraser AG. Pharmacokinetic interactions between alcohol and other drugs. Clin Pharmacokinet 1997;33:79-90. PubMed
  2. Zilkens, R. R., Burke, V., Hodgson, J. M., Barden, A., Beilin, L. J., and Puddey, I. B. Red wine and beer elevate blood pressure in normotensive men. Hypertension 2005;45(5):874-879. PubMed
  3. Potter, J. F., Watson, R. D., Skan, W., and Beevers, D. G. The pressor and metabolic effects of alcohol in normotensive subjects. Hypertension 1986;8(7):625-631. PubMed
  4. Puddey, I. B., Beilin, L. J., Vandongen, R., Rouse, I. L., and Rogers, P. Evidence for a direct effect of alcohol consumption on blood pressure in normotensive men. A randomized controlled trial. Hypertension 1985;7(5):707-713. PubMed
  5. Puddey, I. B., Beilin, L. J., Vandongen, R., and Rouse, I. L. A randomized controlled trial of the effect of alcohol consumption on blood pressure. Clin Exp Pharmacol Physiol 1985;12(3):257-261. 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

Beer Also Interacts With Other Medications

Beer has 654 major, 271 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 654 Moderate 271 No known interaction 1,905 (incl. Guanethidine Monosulfate)
Taking anything else?

Check Another of Your Medications Against Beer

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

Everything else you take

See Every Supplement That Interacts With Guanethidine Monosulfate

This page covers Beer 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

How much people look this up

Where Beer 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 Beer
Top 25%

#333 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 Beer

What is Beer?

Beer
  • Social and recreational drinking
  • Relaxation
  • Heart health (popular belief)
  • Bone health (popular belief)
  • Source of antioxidants and B vitamins

Beer is an alcoholic beverage that contains some minerals, B vitamins, and plant compounds from hops and grain, but it is not a health supplement. Any possible benefits come only from light-to-moderate intake, and they are easily outweighed by the well-known harms of alcohol. The safest amount of alcohol for health is none, and beer should be avoided in pregnancy and breastfeeding.

Read the full Beer monograph & all interactions
Keep checking

Other Drugs & Beer

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

654Major
271Moderate
0Minor
1,904No known interaction
654 Major 271 Moderate 1,904 No interaction
Major

654 interactions

Showing 60 of 654 major interactions — see all 654 on the Beer page.

Moderate

271 interactions

Showing 60 of 271 moderate interactions — see all 271 on the Beer page.

No interaction 1,904 drugs checked — show the list

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

Showing the 60 most looked-up of 1,904 medications checked with no known interaction — see the full Beer list.

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

Can you take Beer 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 Beer 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 Beer?

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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.