Pau d Arco
BignoniaceaeHandroanthus impetiginosus
Also known as: Lapacho, Taheebo, Ipe Roxo
clinical_notes Clinical Summary
Pau d Arco (Handroanthus impetiginosus) is an Amazonian rainforest tree whose inner bark has been used for centuries for fungal infections, bacterial infections, and inflammation.
The key bioactives lapachol and beta-lapachone have demonstrated potent antifungal activity comparable to ketoconazole in vitro.
Human clinical evidence is limited; best evidence is for prevention of oral mucositis in head and neck cancer radiotherapy and reduction of dysmenorrhea pain.
The anticoagulant effect of lapachol requires monitoring when used concurrently with warfarin.
Pregnancy is an absolute contraindication due to embryolethal effects of lapachol in animal studies.
Pregnancy Safety
Absolutely contraindicated. Lapachol has documented fetotoxic and embryolethal effects in animal models. No use during pregnancy under any circumstances.
Lactation Safety
Insufficient safety data. Avoid during breastfeeding.
warning Contraindications
- Pregnancy (contraindicated)Theoretical
- Anticoagulants (warfarin, heparin) (avoid)Theoretical
- Liver or kidney disease (caution)Clinically Proven
vital_signs Clinical Profile
Primary Indications
- check_circle candida and yeast infections
- check_circle fungal infections
- check_circle Helicobacter pylori
- check_circle bacterial infections
- check_circle inflammation
- check_circle skin conditions
- check_circle cancer support (adjunctive)
- check_circle dysmenorrhea
Therapeutic Actions
System Affinities
- check_circle immune
- check_circle integumentary
- check_circle gastrointestinal
labs Active Constituents
lapachol
beta-lapachone
xyloidone
furanonaphthoquinones
anthraquinone-2-carboxylic acid
cyclopentene dialdehydes
flavonoids
iridoid glycosides
phenolic glycosides
fatty acids
history_edu Traditional Use
No TCM data available for this herb yet.
Traditional Uses Across Healing Systems
While many herbs lack controlled clinical trials, centuries of traditional practice across cultures provide valuable insight into their therapeutic applications.
Inner bark decoction used to treat bacterial and fungal infections, fever, syphilis, malaria, and stomach disorders; bark poultice for skin infections and cancer
Named pau d arco (bow stick in Portuguese) for indigenous use in making hunting bows. Long history of use in Brazilian folk medicine and traditional South American healing systems.
Antifungal and antimicrobial support for candida overgrowth, recurrent infections, and as an immunomodulator in integrative oncology
National Cancer Institute research on lapachol conducted 1960-1990; studies discontinued due to toxicity at effective doses. Whole bark is generally considered safer than isolated lapachol.
spa Parts Used
bark
- antifungal for candida
- antimicrobial
- anti-inflammatory
- cancer support
- antiparasitic
Inner bark only; used as decoction (boil 20-30 min), tincture, or standardized capsule. Commercial products vary greatly in lapachol content - quality sourcing is critical. One analysis found only 1/12 commercial products contained measurable lapachol.
shield Safety
Contraindications — Evidence Basis
Pregnancy
Lapachol has documented fetotoxic effects in animal studies including embryolethality and chromosomal abnormalities. Absolutely contraindicated in pregnancy.
Anticoagulants (warfarin, heparin)
Lapachol inhibits vitamin K epoxide and quinone reductases (similar mechanism to warfarin), significantly potentiating anticoagulant effects. Avoid concurrent use; monitor INR if used.
Liver or kidney disease
High-dose lapachol causes dose-dependent hepatotoxic effects in animal studies. One case report of fatal liver failure in a man taking pau d arco with other supplements.
Monitoring Parameters
Monitor during use, especially with prolonged or high-dose therapy.
INR / Prothrombin time
Baseline and within 1-2 weeks of initiation if patient is on anticoagulantsLapachol inhibits vitamin K epoxide reductase, significantly potentiating warfarin and other anticoagulants
flagThreshold: INR >3.0 in patients on warfarin: reduce anticoagulant dose; consult prescriber
Toxicity
High doses of isolated lapachol (>1.5 g/day) cause nausea, vomiting, internal bleeding, anemia
Nausea, vomiting, urine discoloration, internal bleeding, anemia; anaphylaxis (occupational, from tree dust)
Discontinue use. For anticoagulant overdose: Vitamin K and standard management. For anaphylaxis: epinephrine, antihistamines. Supportive care.
Adverse Effects
CYP Metabolism
Beta-lapachone is metabolized by hepatic microsomes. Limited human CYP data available. Theoretical interactions with CYP-metabolized drugs require clinical monitoring.
swap_horiz Interactions
Warfarin / Oral Anticoagulants (Heparin, Apixaban, Rivaroxaban, Dabigatran)
Class: Anticoagulant
Lapachol, the principal active constituent of pau d'arco, inhibits both vitamin K epoxide reductase (VKOR) and vitamin K quinone reductase — the same enzymatic targets as warfarin. This pharmacodynamic synergy can dramatically increase anticoagulant effect and risk of serious or life-threatening bleeding.
Pau d'arco should be avoided in patients on warfarin or other anticoagulants. If concomitant use is unavoidable, monitor INR very closely (every 3-5 days initially). Discontinue pau d'arco and seek urgent medical attention if unexpected bleeding occurs.
Antiplatelet Agents (Aspirin, Clopidogrel, Ticagrelor, Dipyridamole)
Class: Antiplatelet
Lapachol and beta-lapachone have demonstrated antiplatelet activity, inhibiting platelet aggregation and affecting arachidonic acid metabolism. Combined with antiplatelet drugs, additive inhibition of platelet function significantly increases bleeding risk.
Avoid concurrent use of pau d'arco with antiplatelet drugs without close medical supervision. Discontinue pau d'arco at least 2 weeks before any surgical or invasive procedure. Report bruising or prolonged bleeding to the prescriber.
Immunosuppressants (Cyclosporine, Tacrolimus, Azathioprine, Mycophenolate)
Class: Immunosuppressants
Pau d'arco has immunomodulatory properties mediated by lapachol and beta-lapachone, which affect T-cell function and cytokine production. These immunostimulatory effects may antagonize immunosuppressive drug regimens in transplant patients, potentially precipitating rejection episodes.
Pau d'arco is generally contraindicated in solid organ transplant recipients on immunosuppressive therapy. If a patient is using pau d'arco, monitor drug levels of immunosuppressants and assess for early graft rejection signs. Advise discontinuation.
Chemotherapy Agents (Cisplatin, Cyclophosphamide, Doxorubicin, Irinotecan)
Class: Antineoplastic
Beta-lapachone induces apoptosis in cancer cells via mitochondrial signaling and caspase activation. Clinical trials in the 1970s showed lapachol had unacceptable toxicity at doses needed for antineoplastic efficacy, including nausea, vomiting, and anemia. Combination with standard chemotherapy may increase toxicity without established benefit.
Pau d'arco should not be used as self-medication by patients undergoing chemotherapy without oncology team approval. Advise patients to disclose all herbal products to their oncologist. Monitor for unexpected cytotoxicity or drug interaction.
Antidiabetic Agents (Metformin, Insulin, Sulfonylureas, Glyburide)
Class: Antidiabetics
Beta-lapachone constituents of pau d'arco have been shown to stimulate insulin secretion in experimental pancreatic islet studies. Concurrent use with antidiabetic medications may result in additive glucose-lowering effects and increased risk of hypoglycemia.
Monitor blood glucose in diabetic patients using pau d'arco supplements. Advise patients to watch for hypoglycemic symptoms. Clinical significance at normal tea doses is uncertain; no dose adjustment needed unless hypoglycemia is documented.
hub Combinations
Synergistic pairings can enhance therapeutic outcomes, while knowing suitable substitutes helps when specific herbs are unavailable or contraindicated.
Synergistic Combinations
2Black Walnut
Traditional UseBoth have antifungal (candida) and antiparasitic activity through different mechanisms: lapachol/beta-lapachone (Pau d'Arco) and juglone (Black Walnut). Enhanced spectrum of antimicrobial coverage.
Traditional combination in antiparasitic protocols; no direct RCT data.
Cat's Claw
Traditional UseBoth are Amazonian rainforest herbs with antimicrobial and immunomodulatory properties. Cat's Claw provides complementary alkaloid-based immune modulation while Pau d'Arco contributes naphthoquinone antimicrobial activity.
Traditional Amazonian combination; limited clinical trial data for the specific pairing.
science Studies
Effects of Handroanthus impetiginosus (Mart. ex DC.) Mattos extract on inflammatory, immune, atherogenic profile and differentiation in THP-1 cell line
In VitroThis in vitro study examined the anti-inflammatory and immunomodulatory properties of Handroanthus impetiginosus extract in the THP-1 human monocyte/macrophage cell line model. Plant extract treatment reduced pro-inflammatory cytokine production and also decreased the uptake of modified LDL-derived cholesterol by THP-1 cells, suggesting potential anti-atherogenic effects. The study demonstrates that H. impetiginosus has anti-inflammatory and immunomodulating properties in human cell models, providing a mechanistic foundation for further investigation in higher-order models and clinical trials.
The medicinal plant Tabebuia impetiginosa potently reduces pro-inflammatory cytokine responses in primary human lymphocytes
In VitroThis in vitro immunology study tested multiple extracts of Handroanthus impetiginosus bark on primary human peripheral blood mononuclear cells (PBMCs) to assess immunomodulatory effects on cytokine production. Different extracts produced unique cytokine profiles with some extracts potently suppressing PMA/ionomycin-activated cytokines including IFN-gamma, IL-1beta, IL-2, IL-6, TNF, and MCP-1. Notably, some extracts outperformed a positive control used clinically for immune suppression. The study confirms and quantifies the significant immunomodulatory activity of H. impetiginosus in human primary immune cells.
medication Dosing
decoction
1-2 tablespoons dried inner bark per quart water
2-3 cups/day
Boil gently 20-30 min. The active naphthoquinones are partially water-soluble but better extracted at simmering temperatures. Quality of product varies widely; verify lapachol content if possible.
capsule
500-1000 mg dried bark powder
2-3x/day
250-3750 mg/day range used in research. Standard starting dose 500 mg TID. Standardized for lapachol content when available.
Disclaimer: This information is largely AI-generated and reviewed by human experts at Evara Health. It is intended for educational and clinical reference purposes only and should not replace professional medical advice.
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