Drug & supplement interaction

Logwood + Rifapentine

Rifapentine brand name: Priftin.

No Known Interaction
Medically reviewed by · Updated June 2026 · Pair last verified Sep 13, 2026
The bottom line No known interaction

We found no known interaction between Logwood and Rifapentine 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 Rifapentine states a food rule worth keeping to.

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Interaction report

Logwood and Rifapentine

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 Rifapentine and Logwood 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.

Worth understanding: our licensed dataset holds no drug-interaction record for Logwood at all — not against Rifapentine, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.

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.

Logwood safety at a glance

Logwood overall Not established Logwood is used mainly as a dye, and its safety as a supplement has not been well studied in people.
Pregnancy Avoid There is no reliable safety information, so it is best avoided during pregnancy.
Breastfeeding Avoid There is no reliable safety information, so it is best avoided while breastfeeding.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Rifapentine and Logwood? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

What Rifapentine’s Own FDA Label Lists

This is not an interaction — none of it involves Logwood. These are the most notable effects listed in the ADVERSE REACTIONS section of Rifapentine’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.

  • Thoughts of self-harm Worth acting on
  • Severe muscle breakdown Worth acting on
  • High potassium Worth acting on
  • Blood clots Worth acting on
  • Pancreatitis Worth acting on
  • Yellowing of the skin or eyes Worth acting on
  • High blood sugar Worth acting on
  • Fainting Worth acting on
  • Wheezing Worth acting on
  • Confusion Worth acting on

Showing the 10 most notable of 52 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 Rifapentine. Read the label on DailyMed › Logwood’s licensed record lists no adverse effects our clinical vocabulary could match, so there is no Logwood side to compare — that is a limit of the record, not a statement that Logwood has no side effects.

How to take them

Some Rifapentine Products Have a Food Rule — Logwood Should Not Break It

At least one FDA label for a product containing Rifapentine says to take it with food. If you take Logwood on an empty stomach out of habit, keep them separate — and take Rifapentine 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 Rifapentine 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.

( 2.2 ) Take with food.

From the Dosage and Administration section of the FDA label we read for Rifapentine — 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 Rifapentine

This page covers Logwood only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Rifapentine page lists 64 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Alkanna (moderate), Alpine Ragwort (moderate), Bacillus Coagulans (moderate) and Bacillus Subtilis (moderate).

By severity: 1 major · 53 moderate · 10 minor.

From our pharmacist’s overview on the Rifapentine page

“Rifapentine (Priftin) treats tuberculosis and is often dosed just once or twice a week, so a single blunted dose costs more than it would with a daily pill. That is why I read this list of 64 interacting supplements as a real warning rather than routine fine print.”

Reviewed by 2 · Jul 18, 2026

Open the Rifapentine interaction page

How much people look this up

Where Logwood and Rifapentine 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 Logwood
Steady interest

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

29 days ago today
Medication Rifapentine
Steady interest

#2,337 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. Logwood is not yet covered by that licensed database, so its write-up cites publicly available medical sources directly (see the references below).
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Logwood reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Logwood and Rifapentine records this page draws on were last updated June 22, 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 Logwood

What is Logwood?

  • Astringent for diarrhea (traditional)
  • Wound and skin care (traditional)
  • Digestive complaints (traditional)
  • Source of dye for textiles and laboratory staining

Logwood is a tropical hardwood best known as the source of the dyes hematoxylin and hematein, which are widely used to stain tissue in laboratories. It has a history of folk use as an astringent for diarrhea and skin problems, but there is very little modern human research to support any health benefit, so it is not recommended as a dietary supplement.

Haematoxylum campechianum · Fabaceae · Heartwood (and the dye/extract hematoxylin derived from it) · Wood chips, extracts, and dye/stain preparations; rarely used as a tea or supplement

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

Logwood: dosing

There is no established or standardized dose for logwood as a dietary supplement. It is not a common commercial supplement, and reliable dosing information from clinical studies does not exist.If you come across a product that contains logwood, follow the directions on the label and do not exceed them.

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

Read the full Logwood monograph & all interactions
Medication

About Rifapentine

What Is Rifapentine Used For?

Brand name: Priftin

Rifapentine tablets — sold as Priftin and as rifapentine tablets — are used to treat two forms of tuberculosis caused by Mycobacterium tuberculosis. For active pulmonary TB (a live TB infection in the lungs), it is approved for adults and children 12 years and older. It must always be combined with other anti-TB drugs — never taken alone.

For latent tuberculosis infection (LTBI) — where TB bacteria are in the body but not yet causing illness — it is approved for adults and children 2 years and older who are at high risk of the infection becoming active. For LTBI, it is always taken together with isoniazid, once weekly for 12 weeks. Active TB disease must be ruled out before starting LTBI treatment.

Most-Reported Side Effects for Rifapentine

From FAERS, the FDA’s public side-effect reporting system (509 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Fever 66 reports
Nausea 52 reports
Fatigue 42 reports
Hypertension 40 reports
Vomiting 40 reports
See full Rifapentine drug information
Keep checking

Other Drugs & Logwood

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

0Major
0Moderate
0Minor
2,829No known interaction
2,829 No interaction
No interaction 2,829 drugs checked — show the list

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

Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full Logwood list.

See the full Logwood interactions page
See every supplement checked against Rifapentine, ranked by severity
Evidence & sources

Logwood References

The 2 sources that drive our Logwood monograph — publicly available pages from reputable medical and government organizations. Every link was verified to work before publishing. Logwood is not covered by the licensed Natural Medicines interaction database, so its page cites these public sources directly.

  1. Drugs and Supplements — MedlinePlus (U.S. National Library of Medicine) Source
  2. Using Dietary Supplements Wisely — NIH National Center for Complementary and Integrative Health (NCCIH) Source

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 Logwood and Rifapentine Together: Common Questions

Is it safe to take Logwood with Rifapentine?
We do not list a known interaction between Logwood and Rifapentine. 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 Logwood and Rifapentine at the same time of day?
At least one FDA label for a product containing Rifapentine says to take it with food. If you take Logwood on an empty stomach out of habit, keep them separate and take Rifapentine with a meal where the label says to. Food instructions belong to the product rather than the ingredient — two Rifapentine products can differ — so check the directions on your own box. This is about absorption, not an interaction.
Does Rifapentine interact with any supplements?
Yes. Rifapentine has documented interactions with 64 supplements in our database — Logwood is not one of them. The Rifapentine 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

Logwood monograph Uses, safety profile, and every drug interaction in one place Rifapentine drug information The full plain-English guide to this medication Rifapentine supplement interactions Every supplement checked against Rifapentine, 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 Rifapentine and Logwood?

Our pharmacists answer your medication & supplement questions — free.

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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.