Interactions Between Herbal Medicines and Prescribed Drugs

  title={Interactions Between Herbal Medicines and Prescribed Drugs},
  author={Angelo A. Izzo and Edzard Ernst},
Despite the widespread use of herbal medicines, documented herb-drug interactions are sparse. We have reviewed the literature to determine the possible interactions between the seven top-selling herbal medicines (ginkgo, St John’s wort, ginseng, garlic, echinacea, saw palmetto and kava) and prescribed drugs. Literature searches were performed using the following databases: Medline (via Pubmed), Cochrane Library, Embase and phytobase (all from their inception to July 2000). All data relating to… 

Clinical evidence of herbal drugs as perpetrators of pharmacokinetic drug interactions.

The available evidence indicates that, at commonly recommended doses, none of these herbs act as potent or moderate inhibitors or inducers of cytochrome P450 (CYP) enzymes or P-glycoprotein (ABCB1) in Echinacea, garlic, gingko, ginseng, goldenseal, and milk thistle.

An Overview of the Evidence and Mechanisms of Herb–Drug Interactions

The potential for HDI should always be assessed in the non-clinical safety assessment phase of drug development process and an increased level of awareness of HDI is necessary among health professionals and drug discovery scientists.

The Clinical Importance of Herb-Drug Interactions and Toxicological Risks of Plants and Herbal Products

This review can be used as a quick reference database for physicians and healthcare professionals involved in therapy, aiming to maximize clinical outcomes by reducing the negative and toxic effects of plants along with avoiding herb-drug interactions.

Herb-drug interactions: an overview of systematic reviews.

The majority of the HMPs evaluated in systematic reviews were not associated with drug interactions with serious consequences, however, the poor quality and the scarcity of the primary data prevent firm conclusions.

Cytochrome P450 enzyme mediated herbal drug interactions (Part 2)

Though there were few clinical studies on potential CYP-mediated interactions produced by kava, present data suggest that kava supplements have the ability to inhibit CYP1A2 and CYP2E1 significantly, and precaution should be exercised when patients are taking Chinese herbal medicines concomitantly with drugs that are CYP substrates.

Effects of herbal supplements on drug glucuronidation. Review of clinical, animal, and in vitro studies.

Evaluated evidence on the glucuronidation of phytochemicals and the potential for UGT-mediated herb-drug interactions with the top-selling herbal supplements in the United States and Europe and the need for further research to determine the clinical consequences of these interactions is highlighted.

Review on mechanisms and interactions in concomitant use of herbs and warfarin therapy.

Safety monitoring of herb-drug interactions: a component of pharmacovigilance.

The authors' objective for this paper is to provide awareness among policy makers responsible for the design of appropriate pharmacovigilance practices and therefore to highlight the importance of pharmacov Vigilance in the safety monitoring of HDIs.

Herb-Drug Interactions

An extensive review of the literature identified reported herb-drug interactions with clinical significance, although the underlying mechanisms for the altered drug effects and/or concentrations by concomitant herbal medicines are yet to be determined.



Herbal remedies: adverse effects and drug interactions.

Physicians must be alert for adverse effects and drug interactions associated with herbal remedies, and they should ask all patients about the use of these products.

Herb-drug interactions

Potential Metabolic Interaction between St. John's Wort and Theophylline

The increase in theophylline concentrations observed in this patient after discontinuation of St. John’s wort suggests that components of this herbal supplement may have induced hepatic enzymes (namely, CYP1A2) necessary for theophyLLine clearance.

Herbal medicines: where is the evidence?

  • E. Ernst
  • Medicine
    BMJ : British Medical Journal
  • 2000
An increasing body of evidence is now emerging from systematic reviews and meta-analyses of randomised clinical trials that suggest that some herbal medicines are efficacious, and are likely to convince sceptics.

Assessing the risks and benefits of herbal medicine: an overview of scientific evidence.

The history and current use of plant-based medicine is summarized and the evidence of the risks and benefits associated with 6 plants is highlighted and evidence from randomized controlled trials and meta-analyses is evaluated.

Dietary supplement-drug interactions.

This review focuses on possible interactions between drugs and herbal medicines used for phytoestrogen-hormone and antiplatelet-oral anticoagulant therapy, and recommends for counseling patients at highest risk of adverse interactions.

Traditional Remedies and Food Supplements

Case series have been identified which substantiate previous reports, including liver problems following the use of Chinese herbal medicine for skin disorders, allergic reactions to royal jelly and propolis and heavy metal poisoning caused by remedies from the Indian subcontinent.

A review of the benefits, adverse events, drug interactions, and safety of St. John's Wort (Hypericum perforatum): the implications with regard to the regulation of herbal medicines.

  • M. McIntyre
  • Medicine
    Journal of alternative and complementary medicine
  • 2000
The effective banning in Ireland of St. John's wort and a number of other botanicals on January 1, 2000 came as a seismic shock to herbal manufacturers, practitioners, retailers, and the Irish public alike, calling into question the future of herbal medicine throughout the European Union.

The efficacy of ginseng. A systematic review of randomised clinical trials

It is concluded that the efficacy of ginseng root extract is not established beyond reasonable doubt for any of these indications and the widespread use ofginseng as a herbal remedy warrants more rigorous investigations to assess its efficacy and safety.

St. John's Wort and Antidepressant Drug Interactions in the Elderly

A series of five cases of clinically diagnosed central serotonergic syndrome among elderly patients who combined prescription antide pressants with St. John's wort requires further evaluation due to potential for drug interactions with central ner vous system agents and for more definitive therapeutic indications.