Skip to content

Interactions between herbal medicines and the anticoagulant warfarin

Pharmacokinetic and pharmacodynamic interactions between herbal medicines (cranberry, garlic, echinacea, policosonal, fish oil, CoEnzyme Q10, Soy, feverfew, milk thistle and evening primrose oil) and the anticoagulant warfarin - Randomised clinical trials in healthy male subjects

Status
Completed
Phases
Phase 1
Study type
Interventional
Source
ANZCTR
Registry ID
ACTRN12607000054415
Enrollment
48
Registered
2007-01-16
Start date
2005-01-24
Completion date
2009-10-26
Last updated
2020-01-13

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

None listed

Brief summary

This study will explore the clinical significane of interactions between commonly used herbal medicines with the anti-coagulant warfarin. In total 5 independent three- treatment cross over randomnised clinical trials will be conducted with similar study design. In each trial 2 herbs will be studied.

Interventions

In each 3-treatment cross over clinical trial 2 herbal medicine will be studied. Dosage of the herbal medicines mentioned here are based upon the current information and subject to change in accordence with the latest clinical evidence which will be decided prior to each clinical trial. Variations in pharmacokinetics and pharmacodynam

In each 3-treatment cross over clinical trial 2 herbal medicine will be studied. Dosage of the herbal medicines mentioned here are based upon the current information and subject to change in accordence with the latest clinical evidence which will be decided prior to each clinical trial. Variations in pharmacokinetics and pharmacodynamics of warfarin will be compared when single dose of 25 mg warfarin given alone orally (control) and when single dose of 25 mg warfarin given after 2 weeks of pre-treatment with each herbal medicine administered orally (intervention). Herbal medicines intake will be continued for one more week after warfarin administration. In total 10 herbs will be studied in 5 clinical trials. List of the proposed herbs are cranberry (6 X 500mg capsules per day of General Nutrition Corporation (GNC) cranberry juice concentrate capsules), garlic (equivalent to 4 g of fresh garlic), echinacea (4 X 1.27g tablets daily of Medi herb echinacea premium tablets), policosonal (20 mg daily), fish oil (4 g per day), CoEnzyme Q10 (50 mg per day), Soy (3.5 mg per day of phospholipids) , feverfew (100 mg of powdered feverfew daily), Milk thistle (250 mg daily of silymarin) and evening primrose oil (300 mg daily of fixed oil) .

Sponsors

Prof Andrew McLachlan
Lead SponsorIndividual

Study design

Allocation
Randomised controlled trial
Intervention model
Crossover
Primary purpose
Treatment
Masking
Open (masking not used)

Eligibility

Sex/Gender
Male
Age
18 Years to 50 Years
Healthy volunteers
No

Inclusion criteria

Healthy subjects not taking other medicines including any supplements, who are non-smokers.

Exclusion criteria

Any condition with could effect pharmacokinetic and pharmacodynamics of warfarin.

Outcome results

None listed

Source: ANZCTR · Data processed: Feb 4, 2026