Chaparral (Larrea tridentata (DC) Coville, Larrea divaricata Cav) & Nordihydroguaiaretic acid (NDGA)

Category

Synonyms

1 aryl tetralin lignans, chaparral taxa, chaparral tea, chaparro, creosote, creosote bush, dwarf evergreen oak, el gobernadora (Spanish), falsa alcaparra (Spanish), flavonoids, furanoid lignans, geroop, gobernadora, greasewood, guaiaretic acid, guamis, gumis, hediondilla, hideonodo, hydrocarbons, jarillo, kovanau, kreosotstrauch, larrea, Larrea divaricata, Larrea glutiosa, Larrea mexicana, Larrea mexicana Moric, Larrea tridentate, Larrea tridentata (DC) Coville, lignans, maltose-M3N, M4N, NDGA, nordihydroguaiaretic acid, Nordy, palo ondo (Spanish), sapogenins, shoegoi, sonora covillea, sterols, tasago, triterpenes, volatile oils, wax esters, ya-tmep, yah-temp, Zygophyllaceae (family).

Background

Chaparral is a shrub found in the desert regions of southwestern United States and Mexico. It was used by Native American populations for indications including chicken pox (varicella), colds, diarrhea, menstrual cramps, pain, rheumatic diseases, skin disorders, snake bites, and as an emetic. Chaparral tea was also used for purported effects of removing lysergic acid diethylamide (LSD) residue and thereby preventing recurrent hallucinations. Chaparral leaves have also been used externally for bruises, scratches, wounds, and hair growth.

The chaparral component nordihydroguaiaretic acid (NDGA) has been evaluated as a treatment for cancer but, due to risk of toxicity, it is considered unsafe and not recommended for use.

Evidence

Cancer: Chaparral and one of its components called nordihydroguaiaretic acid (NDGA) have antioxidant ("free-radical scavenging") properties and have been proposed as cancer treatments. However, chaparral and NDGA have been linked with cases of kidney and liver failure, liver cirrhosis, kidney cysts, and kidney cancer in humans. In response to these reports, the U.S. Food and Drug Administration (FDA) removed chaparral from its "Generally Recognized as Safe" (GRAS) list in 1970. Chaparral and NDGA are generally considered unsafe and are not recommended for use.
Grade: C

Tradition

Dosing

Adults (18 years and older)

Safety has not been established for any dose. Small doses of tea have been used; for example, 1 teaspoon of chaparral leaves and flowers steeped in 1 pint of water for 15 minutes, consumed 1-3 cups daily for up to a maximum of several days. Chaparral tea has also been made by steeping 7-8 grams of crumbled dried leaves, stems, and twigs in one quart of hot water. As a water extract, chaparral might be consumed in the amount of one to three cups of chaparral tea per day for a period of two to three weeks, although this is not recommended.

A tincture has also been used; for example, 20 drops up to three times daily. These preparations may be associated with less toxicity, and possibly contain fewer allergenic compounds than capsules or tablets. Oil or powder forms of chaparral have also been used, applied to an affected area of skin several times daily.

Capsules or tablets may deliver large doses leading to toxicity, and are not recommended. Exposure to lignans, which may yield toxicity, appears to be greater from capsules or tablets than from chaparral tea.

Children (younger than 18 years)

Chaparral is not recommended for use in children, due to lack of scientific data and potential toxicity.

Safety

Allergies

People with allergy/hypersensitivity to chaparral or any of its components including nordihydroguaiaretic acid (NDGA), nor-isoguaiasin, dihydroguaiaretic acid, partially demethylated dihydroguaiaretic acid, and demethoxyisoguaiasin may have allergic reactions to chaparral.

There are human case reports of allergic hypersensitivity (contact dermatitis) to chaparral and to its resin.

Side Effects and Warnings

Chaparral has been associated with multiple serious and potentially fatal adverse effects in animals and humans. Animals given the chaparral component nordihydroguaiaretic acid (NDGA) developed kidney or gastrointestinal cysts and liver cell death. In humans, chaparral has been associated with kidney and liver failure, liver cirrhosis, kidney cysts, and kidney cancer. Human case reports note rash and fever with use of chaparral. Nausea, vomiting, diarrhea, abdominal cramps, and mouth inflammation have also been reported in people consuming chaparral. Exposure to lignans, which may yield toxicity, appears to be greater from capsule or tablets than from decoctions of chaparral tea. The U.S. Food and Drug Administration (FDA) removed chaparral from the "Generally Recognized as Safe" (GRAS) list in 1970, and considers chaparral to be unsafe. Elevations of liver enzymes or altered kidney function tests (serum creatinine) may occur with chaparral.

Based on an animal study, chaparral may lower blood sugar levels. Caution is advised in patients with diabetes or hypoglycemia and in those taking drugs, herbs, or supplements that affect blood sugar. Serum glucose levels should be monitored closely and medication adjustments may be necessary. Aggravation of hypothyroidism may occur.

In theory, chaparral may also increase the risk of bleeding and may add to the effects of anticoagulants (blood thinners) or antiplatelet drugs. Use of chaparral with any of these drugs should be discussed with a healthcare professional.

Pregnancy & Breastfeeding

Chaparral cannot be recommended during pregnancy or breastfeeding because of the risk of birth defects or spontaneous abortion.

Chaparral may inhibit ovulation and decrease the chance that women will become pregnant.

Interactions

Interactions with Drugs

Based on animal studies and human case reports, chaparral has been associated with kidney damage, cysts, cancer, and kidney failure. Theoretically, use of chaparral with other agents known to alter kidney function or induce toxicity should be avoided, including sulfa antibiotics, aminoglycoside antibiotics, COX-2 inhibitors, NSAIDs, and a number of other drugs. Patients who are using other medications and who are considering chaparral should consult with a qualified healthcare professional, including a pharmacist. Based on animal study and human case reports, chaparral has also been associated with liver damage. Theoretically, the use of chaparral with other agents known to induce liver toxicity should be avoided; these include amiodarone, carmustine, or danazol.

Based on animal study, chaparral may lower blood sugar levels. Caution is advised when using medications that may also lower blood sugar. Patients taking drugs for diabetes by mouth or injection should be monitored closely by a qualified healthcare professional. Medication adjustments may be necessary. Based on human research, chaparral may increase the risk of bleeding when taken with drugs that also increase the risk of bleeding. Some examples include aspirin, anticoagulants ("blood thinners") such as warfarin (Coumadin®) or heparin, anti-platelet drugs such as clopidogrel (Plavix®), and non-steroidal anti-inflammatory drugs such as ibuprofen (Motrin®, Advil®) or naproxen (Naprosyn®, Aleve®).

Based on animal research, chaparral may interfere with the way the body processes certain drugs using the liver's cytochrome P450 enzyme system. As a result, the levels of these drugs may be increased in the blood and may cause increased effects or potentially serious adverse reactions. Patients using any medications should check the package insert and speak with a qualified healthcare professional or pharmacist about possible interactions. Based on historical use, chaparral may interact with monoamine oxidase inhibitors (MAOIs), such as isocarboxazid (Marplan®), phenelzine (Nardil®), and tranylcypromine (Parnate®). There is also the possibility that blood pressure may become dangerously high if chaparral is taken with MAOIs, although there is limited research supporting this.

Chaparral may aggravate indomethacin-induced gastric ulcers and inhibit the metabolism of barbiturate drugs like phenobarbital. Effects of thyroid medications may be altered although this is unproven.

Chaparral may also interact with cancer, antiviral, gastrointestinal, immunosuppressant, thyroid, and abortion-inducing drugs.

Interactions with Herbs & Dietary Supplements

Based on animal studies and human case reports, chaparral has been associated with kidney damage, cysts, cancer, and kidney failure. Theoretically, the use of chaparral with other herbs or supplements known to alter kidney function or induce toxicity should be avoided; these include agents with high levels of tannins. Chaparral may increase the risk of high blood pressure if used with other herbs with this effect. Based on animal research and human case reports, chaparral has also been associated with liver damage. Theoretically, the use of chaparral with other herbs or supplements known to induce liver toxicity should be avoided.

Based on animal study, chaparral may lower blood sugar levels. Caution is advised when using herbs or supplements that may also lower blood sugar. Blood glucose levels may require monitoring, and doses may need adjustment.

Based on human study, chaparral may increase the risk of bleeding when taken with herbs and supplements that are believed to increase the risk of bleeding. Multiple cases of bleeding have been reported with the use of Ginkgo biloba, and fewer cases with garlic and saw palmetto. Numerous other agents may theoretically increase the risk of bleeding, although this has not been proven in most cases. Chaparral may also interact with vitamin K, which is necessary for blood clotting. By working against the action of vitamin K, chaparral may increase the risk of bleeding.

Based on animal research, chaparral may interfere with the way the body processes certain herbs or supplements using the liver's cytochrome P450 enzyme system. As a result, the levels of other herbs or supplements may become too high in the blood. It may also alter the effects that other herbs or supplements may have on the P450 system. Patients using any medications should check the package insert and speak with a healthcare professional or pharmacist about possible interactions.

Based on historical use, chaparral may interact with herbs or supplements with possible monoamine oxidase inhibitor (MAOI) effects, such as 5-HTP (5-Hydroxytryptophan) or DHEA (dehydroepiandrosterone). Chaparral may also interact with anti-cancer, antioxidant, antiviral, gastrointestinal, immunostimulant, immunosuppressant, and abortion-inducing herbs and supplements.

Effects of thyroid active agents may be altered although this is unproven.

Attribution

This information is based on a professional level monograph edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com): Ethan Basch, MD (Memorial Sloan-Kettering Cancer Center); Samuel Basch, MD (Mt. Sinai Medical Center); Dawn Costa, BA, BS (Natural Standard Research Collaboration); Paul Hammerness, MD (Massachusetts General Hospital); Jenna Hollenstein, MS, RD (Natural Standard Research Collaboration); Howard Moffet, MS, MPH (Kaiser Permanente); Adrianne Rogers, MD (Boston University School of Medicine); Michael Smith, MRPharmS, ND (Canadian College of Naturopathic Medicine); David Sollars MAc, HMC (New England School of Acupuncture); Shaina Tanguay-Colucci, BS (Natural Standard Research Collaboration); Catherine Ulbricht, PharmD (Massachusetts General Hospital); Mamta Vora, PharmD (Northeastern University); Wendy Weissner, BA (Natural Standard Research Collaboration).

Bibliography

Anonymous. From the Centers for Disease Control and Prevention. Chaparral-induced toxic hepatitis: California and Texas, 1992. JAMA 1992;Dec 16, 268(23):3295, 3298.

Anonymous. Chaparral-induced toxic hepatitis: California and Texas, 1992. MMWR Morb Mortal Wkly Rep 1992;Oct 30, 41(43):812-814.

Fleiss PM. Chaparral and liver toxicity. JAMA 9-20-1995;274(11):871-872.

Gimeno MF, Shattner MA, Borda E, et al. Lipoxygenase inhibitors alter aggregation and adhesiveness of human blood platelets from aspirin-treated patients. Prostaglandins Leukot Med 1983;11(1):109-119.

Gordon DW, Rosenthal G, Hart J, et al. Chaparral ingestion: the broadening spectrum of liver injury caused by herbal medications. JAMA 1995;Feb 8, 273(6):489-490.

Heron S, Yarnell E. The safety of low-dose Larrea tridentata (DC) Coville (creosote bush or chaparral): a retrospective clinical study. J Altern Complement Med 2001;7(2):175-185.

Ippen H. Chaparral and liver toxicity. JAMA 1995;Sep 20, 274(11):871. Author reply, 871-872.

Kassler WJ, Blanc P, Greenblatt R. The use of medicinal herbs by human immunodeficiency virus-infected patients. Arch Intern Med 1991;151(11):2281-2288.

Kauma H, Koskela R, Mäkisalo H, et al. Toxic acute hepatitis and hepatic fibrosis after consumption of chaparral tablets. Scand J Gastroenterol. 2004;39(11):1168-71.

Obermeyer WR, Musser SM, Betz JM, et al. Chemical studies of phytoestrogens and related compounds in dietary supplements: flax and chaparral. Proc Soc Exp Biol Med 1995;208(1):6-12.

Smart CR, Hogle HH, Vogel H, et al. Clinical experience with nordihydroguaiaretic acid--"chaparrel tea" in the treatment of cancer. Rocky Mt Med J 1970;67(11):39-43.

Smith AY, Feddersen RM, Gardner KD Jr, et al. Cystic renal cell carcinoma and acquired renal cystic disease associated with consumption of chaparral tea: a case report. J Urol. 1994;152(6 Pt 1):2089-2091.

Stickel F, Schuppan D. Herbal medicine in the treatment of liver diseases. Dig Liver Dis. 2007;39(4):293-304.

Stickel F, Egerer G, Seitz HK. Hepatotoxicity of botanicals. Public Health Nutr 2000;Jun, 3(2):113-124. Comment in: Public Health Nutr 2000;Jun, 3(2):111.

Woolf GM, Petrovic LM, Rojter SE, et al. Acute hepatitis associated with the Chinese herbal product jin bu huan. Ann Intern Med 11-15-1994;121(10):729-735.

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.