Drug & supplement interaction

Arrach + Methdilazine

Methdilazine brand name: Tacaryl.

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

Arrach has a moderate interaction with Methdilazine. Theoretically, concomitant use of arrach can increase risk of adverse effects, as unspecified Chenopodium species are associated with photosensitivity.

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

Arrach and Methdilazine

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

Moderate

PHOTOSENSITIZING DRUGS

Why this applies to Methdilazine

Methdilazine falls under PHOTOSENSITIZING DRUGS — the group Arrach interacts with.

Theoretically, concomitant use of arrach can increase risk of adverse effects, as unspecified Chenopodium species are associated with photosensitivity.
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 thing to know about Methdilazine (Tacaryl): it's an older antihistamine in the phenothiazine family, and like other phenothiazines, it can make your skin more sensitive to sunlight. That means a stronger chance of sunburn or a rash after time outdoors, even on days that wouldn't normally bother you.

Some goosefoot-family plants like arrach have also been linked to photosensitivity. So in theory, taking both could add up and raise that sunburn risk a little more. I want to be honest, though: this is a theoretical concern based on the plant's chemistry, not solid human studies, and there's very little good research on arrach overall. To be safe, use sunscreen, cover up outside, and check with your pharmacist or doctor before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.

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

Arrach Also Interacts With Other Medications

Arrach has 334 moderate known drug interactions in our database — the Methdilazine one above is one of them. If you take anything else, check it against the full list below.

Moderate 334 No known interaction 2,496 (incl. Methdilazine)
Taking anything else?

Check Another of Your Medications Against Arrach

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

Everything else you take

See Every Supplement That Interacts With Methdilazine

This page covers Arrach only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Methdilazine page lists 37 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Alfalfa (moderate), Angelica Archangelica (moderate), Bergamot (moderate) and Bishop's Weed (moderate).

By severity: 1 major · 26 moderate · 10 minor.

From our pharmacist’s overview on the Methdilazine page

“If methdilazine (Tacaryl), a sedating phenothiazine antihistamine used for itching and allergies, is your prescription, read this list with real care. Its one major-rated interaction is activated charcoal, which can soak up the drug in your gut so less of it reaches you.”

Reviewed by 2 · Jul 18, 2026

Open the Methdilazine interaction page

How much people look this up

Where Arrach and Methdilazine 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 Arrach
Top half

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

29 days ago today
Medication Methdilazine
Top 25%

#699 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 Arrach

What is Arrach?

Arrach
  • Painful menstruation
  • Nervous complaints
  • Digestive upset
  • Wound care
  • Insect repellent

Arrach (Chenopodium vulvaria) is a strong-smelling European herb that has been used in traditional folk medicine, mainly for menstrual and nervous complaints. There is very little modern scientific evidence to show that it works or is safe, so it is not recommended, especially during pregnancy or breastfeeding. Talk to your pharmacist or doctor before using any herbal product.

Read the full Arrach monograph & all interactions
Keep checking

Other Drugs & Arrach

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

0Major
334Moderate
0Minor
2,495No known interaction
334 Moderate 2,495 No interaction
Moderate

334 interactions

Showing 60 of 334 moderate interactions — see all 334 on the Arrach page.

No interaction 2,495 drugs checked — show the list

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

Showing the 60 most looked-up of 2,495 medications checked with no known interaction — see the full Arrach list.

See the full Arrach interactions page
See every supplement checked against Methdilazine, 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
Arrach monograph › Uses, safety, and every drug interaction in one place Methdilazine supplement interactions › Every supplement checked against Methdilazine, 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 Arrach and Methdilazine Together: Common Questions

Can you take Arrach with Methdilazine?
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 Arrach and Methdilazine 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 Methdilazine and Arrach?

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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.