Cat’s Claw Side Effects: 7 Risks and Interactions to Know

Is cat’s claw safe?

Cat’s claw is generally well tolerated by most adults at usual doses for short periods, but that does not mean it is risk-free. Knowing the possible cat’s claw side effects is essential before you start, especially if you take regular medicines or have an immune condition. Here are 7 side effects and interactions worth knowing.

Common cat’s claw side effects

1. Digestive upset

The most commonly reported complaints are nausea, diarrhoea and stomach discomfort. Taking the capsules with food, as the NOW Cat’s Claw label suggests, may reduce these cat’s claw side effects.

2. Dizziness and low blood pressure

Cat’s claw may lower blood pressure slightly, which can cause dizziness, especially when standing up quickly. The risk is higher if you already take blood-pressure medicines.

3. Rare kidney and liver reports

Rare but serious cat’s claw side effects include kidney or liver problems. It was not always proven to be the cause, but it is reason enough to stop it if you notice yellow eyes, dark urine or swollen ankles.

Who faces more cat’s claw side effects?

4. Pregnancy, breastfeeding and trying to conceive

Cat’s claw should not be used during pregnancy or breastfeeding. The Solaray Cat’s Claw label clearly says not to use it during pregnancy or when trying to become pregnant, and NOW does not recommend it for pregnant or nursing women.

5. Autoimmune disease and organ transplants

Because cat’s claw may stimulate parts of the immune system, it could worsen conditions such as lupus or multiple sclerosis, or weaken the effect of anti-rejection drugs after a transplant. Anyone on immunosuppressants should avoid it unless their doctor decides otherwise.

Cat’s claw side effects from drug interactions

6. Blood thinners and surgery

Cat’s claw may slightly reduce blood clotting, raising the risk of bleeding with warfarin, aspirin or clopidogrel. For this reason it should be stopped at least 2 weeks before any surgery.

7. Blood-pressure drugs and CYP3A4 medicines

With blood-pressure medicines, pressure may fall too far. Cat’s claw may also affect the liver enzyme CYP3A4, which breaks down many drugs, such as some cholesterol medicines, antifungals and HIV medicines, changing their levels in the blood.

How to reduce cat’s claw side effects

• Stick to the label dose: for NOW, 2 capsules 2 to 3 times daily with food; for Solaray, 1 capsule three times daily with a meal.
• Start at the lowest dose and watch how you feel for a week.
• Show your full list of medicines to your pharmacist.
• Do not stack several anti-inflammatory herbs without advice.
• Stop it and see your doctor if anything unusual happens.

To judge whether the supplement is worth trying, read cat’s claw benefits, and if you have osteoarthritis or rheumatoid arthritis, read cat’s claw for arthritis.

Why do cat’s claw side effects vary between people?

Responses depend on age, other medicines, and kidney and liver health, and the level of active compounds varies between products. Choose a product from a known brand that states the amount of bark per capsule, such as the two 500 mg products above, and avoid unlabelled blends.

Long-term use without follow-up is not advised, because most studies lasted only weeks or a few months and there is little data on long-term safety. Older adults on several medicines are more exposed to interactions and need regular reviews; see joint pain relief for seniors.

When cat’s claw side effects need a doctor

• Severe dizziness or fainting.
• Unusual bleeding or bruising.
• Yellow eyes or skin, or dark urine.
• Reduced urine or swollen feet.
• A flare of an autoimmune condition.

Frequently asked questions about cat’s claw side effects

How soon do cat’s claw side effects appear?

Digestive symptoms usually appear in the first days, while kidney and liver problems are rare and may appear later.

Can I take it with arthritis painkillers?

With paracetamol there is usually no problem, but with anti-inflammatory painkillers the bleeding risk adds up, so ask your doctor.

Is it suitable for people with diabetes?

There is not enough evidence, so check with your doctor and monitor your blood sugar.

Conclusion

Cat’s claw side effects are usually mild, such as nausea, diarrhoea and dizziness, but the real risks lie in pregnancy, autoimmune disease, organ transplants and interactions with blood thinners and blood-pressure drugs. It is not a replacement for rheumatology treatment. You can find NOW Cat’s Claw and Solaray Cat’s Claw at No Style Like pharmacy.

This article was reviewed by the No Style Like pharmacy content team. It is for general awareness only and does not replace advice from your doctor or pharmacist.

Stop cat’s claw 2 weeks before surgery and ask your doctor if you take blood thinners, blood-pressure medicines or immunosuppressants. For more information see the NCCIH cat’s claw page.