Devil’s claw: Dosage. Interactions. Pregnancy Use. Practice Points

2010

Dosage Range

MUSCULOSKELETAL CONDITIONS

• Dried root or equivalent aqueous or hydroalcoholic extracts: 2-6 g daily for painful arthritis; 4.5-9 g daily for lower back pain.

• Liquid extract (1:2): 6-12 mL/day.

• Tincture (1:5): 2-4 mL three times daily.

It is suggested that devil’s claw extracts with at least 50 mg harpagoside in the daily dosage should be recommended for the treatment of pain.

DIGESTIVE CONDITIONS (e.g. DYSPEPSIA)

• Dosages equivalent to 1.5 g/day dried herb are used. It is suggested that devil’s claw preparations be administered between meals, when gastric activity is reduced.

Toxicity

The acute LD50 of devil’s claw was more than 13.5 g/kg according to one study.

Adverse Reactions

Diarrhoea was reported in one clinical study.

Significant Interactions

Devil’s claw has been found to moderately inhibit cytochrome P450 enzymes in vitro, however, the clinical relevance of this is yet to be determined.

WARFARIN

Rare case reports suggest that devil’s claw may potentiate the effects of warfarin, requiring caution and possible dose adjustments; however, clinical testing is required to confirm this — use caution in patients receiving warfarin.

ANTIARRYTHMIC DRUGS

Theoretical interaction exists when the herb is used in high doses; however, clinical testing is required to determine significance — observe patients taking concurrent antiarrythmics.

Contraindications and Precautions

Use cautiously in patients with gastric and duodenal ulcers, gallstones or acute diarrhea, as devil’s claw may cause gastric irritation.

Suspend use of concentrated devil’s claw preparations 1 week before major surgery to avoid increased risk of bleeding.

Pregnancy Use

Devil’s claw is not recommended in pregnancy, as it has exhibited oxytocic activity in animals.

Practice Points / Patient Counselling

• Devil’s claw reduces pain and inflammation and is a useful treatment in arthritis and back pain, according to controlled studies.

• The anti-inflammatory action appears to be different to that of NSAIDs and has not been fully elucidated. There is also preliminary evidence of a chondroprotective effect.

• Preliminary research suggests that it is best to take devil’s claw between meals, on an empty stomach.

• Devil’s claw appears to be relatively safe but should not be used in pregnancy and should be used with caution in peoplewith ulcers or gall stones or in those taking warfarin.

Answers to Patients’ Frequently Asked Questions

What will this herb do for me?

Devil’s claw is a useful treatment for arthritis and back pain. It may also increase appetite and improve digestion and dyspepsia.

When will it start to work?

Results from studies suggest that pain-relieving effects will start within 4-12 weeks.

Are there any safety issues?

Devil’s claw should be used cautiously by people with gallstones, diarrhea, stomach ulcers and those taking the drug warfarin. It is also not recommended in pregnancy.