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

Clinical relevance of St. John's wort drug interactions revisited

The first clinically relevant reports of preparations of St. John's wort (SJW), a herbal medicine with anti‐depressant effects, interacting with other drugs, altering their bioavailability and efficacy, were published about 20 years ago. In 2000, a pharmacokinetic interaction between SJW and cyclosporine caused acute rejection in two heart transplant patients. Since then, subsequent research has shown that SJW altered the pharmacokinetics of drugs such as digoxin, tacrolimus, indinavir, warfarin, alprazolam, simvastatin, or oral contraceptives. These interactions were caused by pregnane‐X‐receptor (PXR) activation. Preparations of SJW are potent activators of PXR and hence inducers of cytochrome P450 enzymes (most importantly CYP3A4) and P‐glycoprotein. The degree of CYP3A4 induction correlates significantly with the hyperforin content in the preparation. Twenty years after the first occurrence of clinically relevant pharmacokinetic drug interactions with SJW, this review revisits the current knowledge of the mechanisms of action and on how pharmacokinetic drug interactions with SJW could be avoided.

Linked Articles

This article is part of a themed section on The Pharmacology of Nutraceuticals. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.6/issuetoc

Hepatotoxicity effect of some Iranian medicinal herbal formulation on rats

Background:

The public conviction that ‘herbal remedies are safe’ has led to an increased consumption of these products. This study was performed in view of the wide distribution of herbal remedies, the risks posed by self-treatment with these products, and the existing reports about the toxic effects of some medicinal herbs.

Materials and Methods:

In this study the effect of some of the most used herbal drops of A, B, C, and D on the liver function of rats was examined at different doses, namely minimum dose, maximum dose, and 2.5 times the maximum dose indicated in the brochures. The rats were administered the said doses via a feeding tube for 50 days. The liver function parameters including aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), alkaline phosphatase (ALP), total serum protein, albumin, and urea were measured using the spectrophotometric method.

Results:

The animals’ liver tissues were examined pathologically. The A drop did not change the liver function parameters significantly. The B drop increased the LDH by 34% compared to the controls, at the maximum administered dose. The C and D drops increased the ALT, AST, and LDH significantly compared to the controls. The histological findings suggest the possible effect of C and D drops on the function of hepatocytes.

Conclusions:

We recommend that the herbal formulations available in pharmaceutical markets be more closely controlled in terms of quality, as well as toxicity, especially with regard to the possible effects on the hepatic function.

Hypericum extract WS ® 5570 for depression--an overview

OBJECTIVE

WS(®) 5570 is a Hypericum (St. John's wort) dry extract that is available as a medicinal product in coated tablets and has a marketing authorisation for the acute treatment of mild to moderate major depression in Germany.

METHODS

This article summarizes the current state of knowledge regarding the clinical efficacy and safety of WS(®) 5570.

RESULTS

In randomised, double-blind, controlled clinical trials the antidepressant effect of the drug was superior to that of the placebo and at least comparable to that of paroxetine. The beneficial effect of WS(®) 5570 is particularly pronounced with respect to the core symptoms of depression. There is evidence that the drug may also be effective in moderate to severe depression and in prophylactic continuation treatment after recovery from an acute episode.

CONCLUSIONS

WS(®) 5570 has a very favourable safety profile, with adverse event rates on one level with placebo and lower than that of synthetic antidepressants in randomised, controlled clinical trials. It may therefore also be an option for patients who do not tolerate other antidepressant drugs. Patients with polydrug treatment should nevertheless use the drug with caution, due to its potential for interactions.

Evaluation of documented drug interactions and contraindications associated with herbs and dietary supplements: a systematic literature review

BACKGROUND AND AIMS

The use of herbs and dietary supplements (HDS) alone or concomitantly with medications can potentially increase the risk of adverse events experienced by the patients. This review aims to evaluate the documented HDS-drug interactions and contraindications.

METHODS

A structured literature review was conducted on PubMed, EMBASE, Cochrane Library, tertiary literature and Internet.

RESULTS

While 85 primary literatures, six books and two web sites were reviewed for a total of 1,491 unique pairs of HDS-drug interactions, 213 HDS entities and 509 medications were involved. HDS products containing St. John's Wort, magnesium, calcium, iron, ginkgo had the greatest number of documented interactions with medications. Warfarin, insulin, aspirin, digoxin, and ticlopidine had the greatest number of reported interactions with HDS. Medications affecting the central nervous system or cardiovascular system had more documented interactions with HDS. Of the 882 HDS-drug interactions being described its mechanism and severity, 42.3% were due to altered pharmacokinetics and 240 were described as major interactions. Of the 152 identified HDS contraindications, the most frequent involved gastrointestinal (16.4%), neurological (14.5%), and renal/genitourinary diseases (12.5%). Flaxseed, echinacea, and yohimbe had the largest number of documented contraindications.

CONCLUSIONS

Although HDS-drug interactions and contraindications primarily concerned a relatively small subset of commonly used medications and HDS entities, this review provides the summary to identify patients, HDS products, and medications that are more susceptible to HDS-drug interactions and contraindications. The findings would facilitate the health-care professionals to communicate these documented interactions and contraindications to their patients and/or caregivers thereby preventing serious adverse events and improving desired therapeutic outcomes.

Complementary Therapies as Adjuncts in the Treatment of Postpartum Depression

Postpartum depression affects an estimated 13% of women who have recently given birth. This article discusses several alternative or complementary therapies that may serve as adjuncts in the treatment of postpartum depression. The intent is to help practitioners better understand the treatments that are available that their clients may be using. Complementary modalities discussed include herbal medicine, dietary supplements, massage, aromatherapy, and acupuncture. Evidence supporting the use of these modalities is reviewed where available, and a list of resources is given in the appendix.

Canadian pharmacy students' knowledge of herbal medicine

OBJECTIVE

To determine fourth-year Canadian pharmacy students' knowledge of herbal medicine and whether that knowledge is associated with mandatory instruction in herbal medicine.

METHODS

Standardized multiple-choice tests assessing students' herbal knowledge were distributed to all fourth-year BSc pharmacy students at 5 pharmacy schools in Canada.

RESULTS

The Quebec response rate was too low to include in the analysis. Herbal knowledge test scores were positively associated with having previously taken an herbal medicine class and completion of a pharmacy practicum. However, postsecondary education, age, and gender were not associated with herbal knowledge test scores. Students at the University of British Columbia had the highest score, followed by Alberta, Nova Scotia, and Ontario.

CONCLUSION

Pharmacy students' knowledge of herbal medicine varies depending on the school attended and higher herbal knowledge test scores appear to be most closely related to mandatory herbal instruction.

Hyperforin, the active component of St. John's wort, induces IL-8 expression in human intestinal epithelial cells via a MAPK-dependent, NF-kappaB-independent pathway

St. John's wort is widely used as an herbal antidepressant and is among the top-selling botanical products in the United States. Although St. John's wort has been reported to have minimal side effects compared with other antidepressants, here we show that hyperforin, the active component of St. John's wort, can stimulate interleukin-8 (IL-8) expression in human intestinal epithelia cells (IEC) and primary hepatocytes. Hyperforin is also able to induce expression of mRNA, encoding another major inflammatory mediator--intercellular adhesion molecule-1 (ICAM-1). IEC participate in the intestinal inflammatory process and serve as a first line of defense through bidirectional communication between host and infectious pathogens. Although hyperforin is a potent ligand for the steroid and xenobiotic receptor (SXR), we found that hyperforin induced IL-8 mRNA through an SXR-independent transcriptional activation pathway. IL-8 induction by hyperforin required the activation of AP-1 but not the NF-kappaB transcription factor, thereby distinguishing it from the NF-kappaB-dependent IL-8 induction mediated by tumor necrosis factor alpha (TNFalpha). Further study revealed that extracellular signal-regulated kinase 1 and 2 (ERK1/2) were required for the hyperforin-induced expression of IL-8. Our results suggest a previously unsuspected effect of St. John's wort in modulating the immune and inflammatory responses.

A Brief History of Time: The Power of Botanical Systematic Reviews

There are more than 20 completed Cochrane systematic reviews on botanical medicine presently published in the Cochrane Library. There are more than 40 that are planned or in progress. It is an opportune time to explore the information needs of readers of botanical systematic reviews and how those needs can be met better by Cochrane systematic reviews. It is proposed that Cochrane systematic reviews focus not only on efficacy but also on expanded safety and quality. Expanded safety refers not only to the occurrence of adverse events but also the contraindications for use such as drug-herb interactions or allergies to products. Quality pertains to whether or not there was a method of standardizing active ingredients in trials and methods for minimizing risks of contamination. Because there are no package inserts to accompany herbal products as there are for drugs, Cochrane systematic reviews offer the ideal forum to present this much-needed information on expanded safety and quality.

The role of alternative medicine in treating postnatal depression

Postnatal depression is a serious and debilitating condition. Due to the perceived stigma of mental illness, the incidence of it is underreported and many mothers refuse psychiatric help either assuming postnatal depression to be normal or because of the potential consequences of having a psychiatric history. Community practitioners who are in contact with new mothers may welcome additional interventions which can enhance the supportive care they give to these women. This article discusses the evidence for a number of these interventions which mothers may find more acceptable than orthodox treatment. The aim of this article is to highlight the possible role of a number of complementary and alternative medicines as adjuncts or alternative treatments for postnatal depression. The interventions discussed in this article include Ayurvedic medicine, herbalism, homeopathy, aromatherapy, massage, hypnosis and traditional Chinese medicine (TCM). With the exception of TCM and Ayurvedic medicine, these interventions have been supported by the House of Lord's Select Committee on Science and Technology (2000) as having an evidence base. Ayurvedic medicine and TCM have been included in this article however, because a number of clients may be using them as their main system of health care--thereby validating the need for information regarding their efficacy. This article is not exhaustive, nor a licence to practice, but is intended as a resource for practitioners with a sound understanding of postnatal depression and conventional treatments whose clients may reject these approaches and be looking for alternative interventions. The final choice of treatment should be the result of discussion between the health visitor and the client and will depend on considerations such as availability, cost and acceptability of the intervention--this article does not, therefore, suggest a 'best option' approach. In addition, it does not address the professional and legal responsibilities of practitioners since these have been well reviewed by Darley (1995), Mantle (1997), Knape (1998) and Rankin-Box (2001).

Kava--the unfolding story: report on a work-in-progress

This paper, originated as a submission (now updated) to the U.K. Medicines Control Agency and Committee of Safety of Medicines (CSM) on January 11, 2002, in response to a report circulated by the German Federal Institute for Drugs and Medical Products (German initials are BfArM), a compilation of which is summarized in Appendix 2. This agency issued notification in late November 2001 of some thirty adverse events associated with the use of concentrated standardized preparations of kava (Piper methysticum, Forst. f.) reported from Germany and Switzerland. An analysis of the summary of the BfArM case reports (see Appendix 2) shows that these contain duplications among the cases cited. The original submission that was sent to the CSM January 2002 has been updated to the version published here. This new version was completed in April 2002. As a result of the alert from BfArM, the evaluation of kava's safety is now occurring on a worldwide basis and, being that this a matter of considerable importance to the public, the health care community, and regulatory authorities as well as to kava farmers throughout Polynesia, it is it important to depict this progress report. As such, this updated report does not provide final answers. The material released by the BfArM is lacking in detail; however, it is hoped that this report will shed light on the kava controversy. It is anticipated that there will be further updates shortly. This report, prepared on behalf of the Traditional Medicines Evaluation Committee, a subcommittee of the European Herbal Practitioners Association, argues that many of the adverse events cited by the BfArM should not be attributed to kava. In addition, the report states that the properties of concentrated standardized kava extracts - as opposed to preparations that closely approximate those created for traditional use - contribute to causing adverse events. This report proposes a number of simple measures that will ensure that safe kava preparations may continue to be available in the United Kingdom.

Interactions between herbal medicines and prescribed drugs: a systematic review

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 herb-drug interactions were included regardless of whether they were based on case reports, case series, clinical trials or other types of investigation in humans. In vitro experiments were excluded. Data were extracted by the first author and validated by the second author. 41 case reports or case series and 17 clinical trials were identified. The results indicate that St John's wort (Hypericum perforatum) lowers blood concentrations of cyclosporin, amitriptyline, digoxin, indinavir, warfarin, phenprocoumon and theophylline; furthermore it causes intermenstrual bleeding, delirium or mild serotonin syndrome, respectively, when used concomitantly with oral contraceptives (ethinylestradiol/desogestrel), loperamide or selective serotonin-reuptake inhibitors (sertaline, paroxetine, nefazodone). Ginkgo (Ginkgo biloba) interactions include bleeding when combined with warfarin, raised blood pressure when combined with a thiazide diuretic and coma when combined with trazodone. Ginseng (Panax ginseng) lowers blood concentrations of alcohol and warfarin, and induces mania if used concomitantly with phenelzine. Garlic (Allium sativum) changes pharmacokinetic variables of paracetamol, decreases blood concentrations of warfarin and produces hypoglycaemia when taken with chlorpropamide. Kava (Piper methysticum) increases 'off' periods in Parkinson patients taking levodopa and can cause a semicomatose state when given concomitantly with alprazolam. No interactions were found for echinacea (Echinacea angustifolia, E. purpurea, E. pallida) and saw palmetto (Serenoa repens). In conclusion, interactions between herbal medicines and synthetic drugs exist and can have serious clinical consequences. Healthcare professionals should ask their patients about the use of herbal products and consider the possibility of herb-drug interactions.

Complementary therapies and health promotion

Nurses have an important role to play in health promotions and it is important that they have a comprehensive knowledge and understanding of the theories of health promotion and conventional interventions. However, they are increasingly likely to be asked about the efficacy of non-conventional interventions and the likelihood of these interventions being of value to the client. This paper offers a review of the evidence to support the role of complementary therapies as adjunctive treatments to enable nurses to discuss their use with their clients as part of their health choice options.

The role of alternative medicine in treating postnatal depression

Postnatal depression is a serious and debilitating condition. Due to the perceived stigma of mental illness, the incidence of it is under-reported and many mothers refuse psychiatric help, either assuming postnatal depression to be normal or because of the potential consequences of having a psychiatric history. Community practitioners who are in contact enhance the supportive care they give to these women. This article discusses the evidence for a number of these interventions which mothers may find more acceptable than orthodox treatment.

St John's wort: Prozac from the plant kingdom

Conventional antidepressants are associated with a range of adverse drug reactions. The herb Hypericum perforatum (St John's wort) might offer another approach to the treatment of depression. Biochemical and animal studies suggest that the phloroglucinol derivative hyperforin is the main active ingredient of St John's wort, and inhibits the synaptosomal uptake of 5-HT, noradrenaline, dopamine, glutamate and GABA. St John's wort has been shown to alleviate symptoms of mild to moderate depression, and seems to offer significant advantages over conventional antidepressants because it is associated with fewer adverse reactions. However, important herb--drug interactions have been described. In view of its efficacy and safety records, St John's wort should be considered for the first-line treatment of mild to moderate depression.