Interactions Between Herbal Medicines and Prescribed Drugs

  title={Interactions Between Herbal Medicines and Prescribed Drugs},
  author={Angelo A. Izzo and Edzard Ernst},
The concomitant use of herbal medicines and pharmacotherapy is wide spread. We have reviewed the literature to determine the possible interactions between seven popular herbal medicines (ginkgo, St John’s wort, ginseng, garlic, echinacea, saw palmetto and kava) and conventional drugs. Literature searches were performed using MEDLINE, Cochrane Library and EMBASE and we identified 128 case reports or case series, and 80 clinical trials.Clinical trials indicate that St John’s wort (Hypericum… 

Drug Interactions with Herbal Medicines

The present article summarizes herbal medicine-drug interactions involving mainly inhibition or induction of cytochrome P450 enzymes and/or drug transporters and describes the clinical implications of these interactions.

Drug interactions between herbal medicines and oral contraceptives

The main interactions that can occur with contraceptives are with popularly used herbal medicines such as licorice, alfalfa, cannabis, cimicifuga, St John's wort, ginseng, kava-kava, saw palmetto, sene, and soy.

Interactions between Herbs and Conventional Drugs: Overview of the Clinical Data

  • A. Izzo
  • Medicine, Biology
    Medical Principles and Practice
  • 2012
An overview of the clinical evidence of interactions between herbal and conventional medicines is provided and healthcare professionals should remain vigilant for potential interactions between herbs and prescribed drugs, especially when drugs with a narrow therapeutic index are used.

Cytochrome P450 enzyme mediated herbal drug interactions (Part 1)

The available evidence indicates that, at commonly recommended doses, other selected herbs including Echinacea, Ginkgo biloba, garlic, goldenseal and milk thistle do not act as potent or moderate inhibitors or inducers of CYP enzymes.

Evaluation of metabolism-mediated herb-drug interactions

Major factors affecting the metabolism of herbal medicines, mechanisms of herb- drug interactions mediated by CYPs and UGTs, and several in vitro methods to assess the herb-drug interactions are described.


This article is a recapitulation of the current research on interactions of Garlic, St. John’s Wort, Ginkgo biloba, Black pepper, Kava-Kava, Ginseng and Ephedra with a number of prescription and OTC

Herbal Drug Interactions

This chapter presents interactions of herbal medicines with other medicines (herbal or non-herbal) and suggests that it becomes important to keep an eye on the use of combination herbal therapy in order to avoid serious results because of interactions with each other.

Controversial Interactions of Tacrolimus with Dietary Supplements, Herbs and Food

The aim of the study is to present selected interactions between tacrolimus and the commonly used dietary supplements, herbs and food and to emphasize the potential interactions between herbal medicines and synthetic drugs.

Herb–Drug and Food–Drug Interactions

Much of the published evidence on herb–drug and food–drug interactions is based on case reports or on pharmacokinetic data alone, and these require substantiation by studies measuring the clinical effects of drugs.

Old and new oral anticoagulants: Food, herbal medicines and drug interactions.




Interactions between herbal medicines and prescribed drugs: a systematic review.

Interactions between herbal medicines and synthetic drugs exist and can have serious clinical consequences, and healthcare professionals should ask their patients about the use of herbal products and consider the possibility of herb-drug interactions.

Herbal medicinals: selected clinical considerations focusing on known or potential drug-herb interactions.

  • L. G. Miller
  • Medicine, Biology
    Archives of internal medicine
  • 1998
Herbal medicinals are being used by an increasing number of patients who typically do not advise their clinicians of concomitant use. Known or potential drug-herb interactions exist and should be

Clinical drugs that interact with St. John's wort and implication in drug development.

The knowledge on clinical interactions of prescribed drugs with SJW and the implication in drug development is updated and new drugs may be designed to avoid drug interactions.

Herb–drug interactions: an overview of the clinical evidence

  • A. Izzo
  • Biology, Medicine
    Fundamental & clinical pharmacology
  • 2005
For many of the interactions discussed here, the understanding of the mechanisms involved is incomplete, and taking herbal agents may represent a potential risk to patients under conventional pharmacotherapy.

Herb-drug interactions: a literature review.

Herbs are often administered in combination with therapeutic drugs, raising the potential of herb-drug interactions. An extensive review of the literature identified reported herb-drug interactions

Interactions between herbal and conventional medicines

Recommendations have been given for health professionals to advise or develop strategies to safeguard patients, without resorting to speculation or scare-mongering on herbal medicines interactions.

Drug interactions with St. John's Wort (Hypericum perforatum): a review of the clinical evidence.

  • A. Izzo
  • Medicine
    International journal of clinical pharmacology and therapeutics
  • 2004
St. John's Wort represents a herbal medicine with a high potential for drug interactions and some of such interactions may have serious clinical consequences.

Clinical assessment of CYP2D6-mediated herb-drug interactions in humans: effects of milk thistle, black cohosh, goldenseal, kava kava, St. John's wort, and Echinacea.

Comparisons of pre- and post-supplementation phenotypic trait measurements revealed significant inhibition of CYP2D6 activity for goldenseal, but not for the other extracts, indicating that adverse herb-drug interactions may result with concomitant ingestion ofgoldenseal supplements and drugs that are CYP1D6 substrates.

Hyperforin in St. John’s wort drug interactions

Clinical studies using SJW preparations with a low hyperforin amount clearly demonstrated the superiority of this plant extract over placebo and its equivalence to imipramine and fluoxetine in the treatment of mild to moderate forms of depression.