Cat's claw (Uncaria tomentosa, Uncaria guianensis) Dosing and Safety

safety

Allergies

Avoid in people with a known allergy or sensitivity to cat's claw, members of the plant family Rubiaceae, or any species of Uncaria, including Uncaria rhynchophylla, which is used in Chinese herbal preparations under the name Gou-Teng.

Side Effects and Warnings

Cat's claw is possibly safe when taken in recommended doses. A freeze-dried aqueous extract of Uncaria guianensis may be safe when taken by mouth for up to four weeks. Extracts of Uncaria tomentosa, free of tetracyclic oxindole alkaloids, may be safe when taken by mouth for up to 24 weeks.
Use cautiously in people who have kidney problems or those taking agents that may harm the kidneys. Cat's claw may cause kidney failure.
Cat's claw may increase the risk of bleeding. Caution is advised in people with bleeding disorders or taking drugs that may increase the risk of bleeding. Dosing adjustments may be necessary.
Cat claw's may cause low blood pressure. Caution is advised in people taking drugs or herbs and supplements that lower blood pressure.
Use cautiously in people who have heart disorders or are taking drugs for heart disorders. Cat's claw may cause abnormal heart rhythms.
Cat's claw may interfere with the way the body processes certain drugs, herbs, or supplements using the liver's "cytochrome P450" enzyme system.
Use cautiously in people taking antioxidants.
Use cautiously in children due to a lack of safety data.
Use cautiously in people who have hormonal disorders. Cat's claw may affect levels of hormones.
Use cautiously in people who have stomach disorders. Cat's claw may cause changes in bowel movements, diarrhea, nausea, and stomach pain.
Use cautiously in people who have dizziness. Cat's claw may cause dizziness.
Use cautiously in people taking agents that may affect nervous system function (anticholinergics), anti-inflammatory agents, or pain relievers. Cat's claw may interact with these agents.
Avoid in pregnant women due to safety concerns. Cat's claw may cause abortion.
Avoid in people who have autoimmune diseases such as lupus or multiple sclerosis (MS), or those taking agents that affect the immune system. Cat's claw may affect the immune system.
Avoid in people with a known allergy or sensitivity to cat's claw, members of the plant family Rubiaceae, or any species of Uncaria, including Uncaria rhynchophylla, which is used in Chinese herbal preparations under the name Gou-Teng.
Avoid in people who are taking agents that may treat retrovirus infections, such as protease inhibitors and non-nucleoside reverse transcriptase inhibitors (NNRTIs). Cat's claw may interact with these drugs.
Cat's claw may also cause bleeding gums, bruising, hives, itching, nosebleed, and red/purple spots on the body.

Pregnancy and Breastfeeding

There is a lack of scientific evidence on the use of cat's claw during pregnancy or breastfeeding. Avoid in pregnant or breastfeeding women, as cat's claw may cause abortion.

dosing

Adults (18 years and older)

Traditionally, cat's claw has been by mouth as a tea, capsule, decoction, extract, or tincture.
To treat arthritis, 100 milligrams of a freeze-dried aqueous cat's claw extract has been taken by mouth daily. Krallendorn® capsules (containing 20 milligrams of radix Uncariae tomentosae) has been taken by mouth three times daily. Vincaria® has been taken by mouth as 100 milligrams daily for four weeks. A dose of 60 milligrams of Uncaria tomentosa extract has been taken by mouth daily for 24-52 weeks. Six cat's claw (Uncaria tomentosa) capsules (Primal Nature Products) have been taken by mouth daily for six months. An extract of 100 milligrams of Uncaria guianensis has been taken by mouth daily for four weeks.
As a cancer treatment, 6.5 grams of dried cat's claw bark has been boiled in water for three hours and taken by mouth for 15 days.
To stimulate the immune system, 250-350 milligrams of C-Med-100® (an aqueous extract of cat's claw) has been taken by mouth 1-2 times daily for 6-8 weeks.

Children (under 18 years old)

There is no proven safe or effective dose for cat's claw in children.

interactions

Interactions with Drugs

Cat's claw may increase the risk of bleeding when taken with drugs that 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®).
Cat's claw may cause low blood pressure. Caution is advised in people taking drugs that lower blood pressure.
Cat's claw 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. People using any medications should check the package insert, and speak with a qualified healthcare professional, including a pharmacist, about possible interactions.
Cat's claw may interact with agents that may affect blood vessel width, agents that may affect heart rate, agents that may affect the immune system, agents that may affect nervous system function (anticholinergics), agents that may harm the kidneys, agents that may promote urination, agents that may treat abnormal heart rhythms, agents that may treat arthritis, agents that may treat Parkinson's disease, agents that may treat retrovirus infections, agents that may treat seizure, anesthestics, antibiotics, anticancer agents, antigout agents, antihistamines, anti-inflammatory agents, antiviral agents, birth control, calcium channel blockers, cholesterol-lowering agents, Disulfiram (Antabuse®), hormonal agents, Metronidazole (Flagyl®), nervous system agents, pain relievers, radioactive agents used to diagnose diseases, scopolamine, and stomach agents.

Interactions with Herbs and Dietary Supplements

Cat's claw 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.
Cat's claw 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 possibly have on the P450 system.
Cat's claw may cause low blood pressure. Caution is advised in people taking herbs or supplements that lower blood pressure.
Cat's claw may also interact with anesthetics, antibacterials, anticancer herbs and supplements, antigout herbs and supplements, antihistamines, anti-inflammatory herbs and supplements, antioxidants, antivirals, birth control, cholesterol-lowering herbs and supplements, herbs and supplements that may affect blood vessel width, herbs and supplements that may affect heart rate, herbs and supplements that may affect the immune system, herbs and supplements that may affect nervous system function (anticholinergics), herbs and supplements that may harm the kidneys, herbs and supplements that may promote urination, herbs and supplements that may treat abnormal heart rhythms, herbs and supplements that may treat arthritis, herbs and supplements that may treat Parkinson's disease, herbs and supplements that may treat nervous system disorders, herbs and supplements that may treat seizure, herbs and supplements that may treat stomach disorders, hormonal herbs and supplements, iron, maca, and pain relievers.