Drug & supplement interaction

Black Horehound + Tafenoquine

Tafenoquine brand names: Krintafel, Arakoda.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between Black Horehound and Tafenoquine in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the label for Tafenoquine states a food rule worth keeping to.

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Interaction report

Black Horehound and Tafenoquine

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Tafenoquine and Black Horehound in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Black Horehound safety at a glance

Black Horehound overall Use caution Limited safety data exist, so use cautiously and talk to a pharmacist first.
Pregnancy Likely Unsafe When used orally; black horehound may affect the menstrual cycle. There is insufficient reliable information available about the safety of black horehound used... Read the full pregnancy detail
Breastfeeding Avoid Safety is unknown, so avoid use while breastfeeding.

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Tafenoquine and Black Horehound? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Tafenoquine

Interactions in our licensed database are recorded against drug classes, not just single drug names. Tafenoquine is filed under a single classification — oral drugs. Black Horehound has documented interactions with 1 drug class — the most serious being dopamine agonists (moderate) — and none of Tafenoquine’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Black Horehound Does Interact With Other Medications

Black Horehound has 23 moderate known drug interactions in our database — Tafenoquine isn’t one of them. If you take anything else, check it against the full list below.

Moderate 23 No known interaction 2,807 (incl. Tafenoquine)
Taking anything else?

Check Another of Your Medications Against Black Horehound

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

What to actually watch for

What Tafenoquine’s Own FDA Label Lists

This is not an interaction — none of it involves Black Horehound. These are the most notable effects listed in the ADVERSE REACTIONS section of Tafenoquine’s own FDA label, for the medication by itself. Knowing the drug’s own list makes it easier to work out the likely cause if something new turns up while you take both. 10 of them are worth acting on rather than waiting out — marked below.

  • Low mood Worth acting on mentioned in 28.6% of FDA reports for Tafenoquine
  • Loss of vision Worth acting on
  • Memory problems Worth acting on
  • Unsteadiness Worth acting on
  • Yellowing of the skin or eyes Worth acting on
  • Fainting Worth acting on
  • A low platelet count Worth acting on
  • Kidney problems Worth acting on
  • Anemia Worth acting on
  • Hives Worth acting on

Showing the 10 most notable of 24 label-listed effects — ranked by how unusual each one is across medicines generally, with serious effects weighted up.

From the ADVERSE REACTIONS section of the FDA label for Tafenoquine. Read the label on DailyMed › Where a percentage is shown, it is the share of 70 voluntary FDA FAERS reports for Tafenoquine that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Black Horehound’s licensed record lists no adverse effects our clinical vocabulary could match, so there is no Black Horehound side to compare — that is a limit of the record, not a statement that Black Horehound has no side effects.

Special populations

Black Horehound in Pregnancy & Breastfeeding

Pregnancy Likely Unsafe

When used orally; black horehound may affect the menstrual cycle. There is insufficient reliable information available about the safety of black horehound used topically or rectally during pregnancy.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

How to take them

Some Tafenoquine Products Have a Food Rule — Black Horehound Should Not Break It

At least one FDA label for a product containing Tafenoquine says to take it with food. If you take Black Horehound on an empty stomach out of habit, keep them separate — and take Tafenoquine with a meal where the label says to.

This may not be true of your version. Food instructions belong to the product, not the ingredient: two Tafenoquine products can carry different directions, and extended-release forms often differ from immediate-release ones. The label we read is quoted below — check the directions on your own box or bottle, or ask your pharmacist, for how to take the exact product you were given.

( 2.1 ) Regimen Name Timing Dosage Loading regimen For each of the 3 days before travel to a malarious area 200 mg (2 of the 100 mg tablets) once daily for 3 days Maintenance regimen While in the malarious area 200 mg (2 of the 100 mg tablets) once weekly – start 7 days after the last loading regimen dose Terminal prophylaxis regimen In the week following exit from the malarious area 200 mg (2 of

From the Dosage and Administration section of the FDA label we read for Tafenoquine — where that label names a specific product, the instruction is that product's. Read the label on DailyMed ›

A food rule is not an interaction — it is about how much of the medicine you absorb. The directions that came with your own product, and your pharmacist, outrank anything on this page.

Everything else you take

See Every Supplement That Interacts With Tafenoquine

This page covers Black Horehound only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Tafenoquine page lists 17 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Coffee Charcoal (moderate), European Mandrake (moderate), Glucomannan (moderate) and Guar Gum (moderate).

By severity: 1 major · 7 moderate · 9 minor.

From our pharmacist’s overview on the Tafenoquine page

“Tafenoquine (Krintafel, Arakoda) protects against malaria, including the relapsing kind that hides in the liver, and every supplement known to interact with it threatens the same thing, how much of the pill actually reaches your blood. That deserves genuine care, since a partly absorbed antimalarial can let parasites survive and resurf…”

Reviewed by 2 · Jul 18, 2026

Open the Tafenoquine interaction page

How much people look this up

Where Black Horehound and Tafenoquine 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 Black Horehound
Steady interest

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

29 days ago today
Medication Tafenoquine
Steady interest

#2,062 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.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Black Horehound reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Black Horehound and Tafenoquine records this page draws on were last updated July 11, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Supplement

About Black Horehound

What is Black Horehound?

Black Horehound
  • Nausea and vomiting
  • Anxiety and nervous tension
  • Sleep problems
  • Mild digestive upset
  • Coughs and respiratory complaints

Black horehound is a traditional European herb mainly used for nausea, mild anxiety, and digestive upset, but high-quality human studies are lacking, so its effectiveness is largely unproven. It has a strong, unpleasant smell and taste, and its safety has not been well studied, so it should be avoided in pregnancy and breastfeeding and used cautiously by everyone else.

Ballota nigra · Lamiaceae · Above-ground parts (flowering tops and leaves) · Tea (infusion), liquid extract, tincture, capsules

An interaction check asks whether these two react with each other — it does not ask whether Black Horehound is a good idea for someone in your situation. Here is what our Black Horehound record says about it on its own.

Black Horehound: dosing

There is no well-established, standardized dose for black horehound. Traditional use has involved teas made from the dried herb and liquid extracts or tinctures, but reliable dosing from quality human studies is not available.If you choose to use a product, follow the directions on the label and do not exceed the recommended amount.

From our Black Horehound monograph — the full record covers uses, side effects and every documented interaction.

Read the full Black Horehound monograph & all interactions
Medication

About Tafenoquine

What Is Tafenoquine Used For?

Brand names: Krintafel, Arakoda

Tafenoquine is used for two distinct purposes depending on the product. Arakoda and Kodatef are used for malaria prophylaxis — that is, preventing malaria in adults 18 and older who are traveling to or living in areas where malaria is present.

Krintafel is used for the radical cure of Plasmodium vivax malaria — meaning it prevents the malaria parasite from coming back (relapsing) in patients 16 and older who are already being treated with chloroquine for an active P. vivax infection. Krintafel is not used to treat an active malaria attack on its own, and it should only be used alongside chloroquine, not other antimalarials.

Most-Reported Side Effects for Tafenoquine

From FAERS, the FDA’s public side-effect reporting system (70 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Depression 20 reports
Anxiety 18 reports
Post-traumatic stress disorder 15 reports
Anger 14 reports
Nausea 14 reports
See full Tafenoquine drug information
Keep checking

Other Drugs & Black Horehound

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

0Major
23Moderate
0Minor
2,806No known interaction
23 Moderate 2,806 No interaction
Moderate

23 interactions

No interaction 2,806 drugs checked — show the list

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

Showing the 60 most looked-up of 2,806 medications checked with no known interaction — see the full Black Horehound list.

See the full Black Horehound interactions page
See every supplement checked against Tafenoquine, ranked by severity
Evidence & sources

Black Horehound References

The 2 references that drive our Black Horehound monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.
  2. Daels-Rakotoarison DA, Seidel V, Gressier B, et al. Neurosedative and antioxidant activities of phenylpropanoids from Ballota nigra. Arzneimittelforschung 2000;50:16-23. PubMed

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Black Horehound and Tafenoquine Together: Common Questions

Is it safe to take Black Horehound with Tafenoquine?
We do not list a known interaction between Black Horehound and Tafenoquine. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
Should I take Black Horehound and Tafenoquine at the same time of day?
At least one FDA label for a product containing Tafenoquine says to take it with food. If you take Black Horehound on an empty stomach out of habit, keep them separate and take Tafenoquine with a meal where the label says to. Food instructions belong to the product rather than the ingredient — two Tafenoquine products can differ — so check the directions on your own box. This is about absorption, not an interaction.
How was the Black Horehound and Tafenoquine combination checked?
Interactions in our licensed database are recorded against drug classes. Tafenoquine is filed under 1 classification, and Black Horehound has documented interactions with 1 drug class — none of Tafenoquine's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Black Horehound interact with any other medications?
Yes. Black Horehound has 23 documented drug interactions in our database — Tafenoquine is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Tafenoquine interact with any supplements?
Yes. Tafenoquine has documented interactions with 17 supplements in our database — Black Horehound is not one of them. The Tafenoquine interaction page linked on this page lists every one, ranked by severity.

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

Where next

Keep Exploring

Black Horehound monograph Uses, safety profile, and every drug interaction in one place Tafenoquine drug information The full plain-English guide to this medication Tafenoquine supplement interactions Every supplement checked against Tafenoquine, 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 References The 2 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Tafenoquine and Black Horehound?

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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.