General practitioners and St. John's Wort: A question of regulation or knowledge?

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Summary

Background

St. John's Wort (SJW), also known as Hypericum perforatum, is a herbal remedy available over-the-counter. There is evidence that it can treat mild to moderate depression but has potential side effects and important drug interactions.

Objective

To determine general practitioners’ (GPs’) knowledge and recommendation of SJW for mild to moderate depression within a climate of widespread community use of complementary therapies and debate about regulation.

Design and setting

Postal survey of a random sample of 350 Australian GPs.

Results

Forty-eight percent responded. One-third (31%) reported recommending SJW to patients with mild to moderate depression. Of these, only one-third (32%) reported specific dosage instructions. Respondents’ knowledge of side effects and interactions was much less than for selective serotonin reuptake inhibitor antidepressants.

Conclusions

Australian GPs know less about safety of SJW than antidepressants and do not widely recommend it to patients. Despite this, many patients use SJW, probably in combination with other pharmaceuticals. Effective dissemination of further research into effectiveness and risk profiles of complementary therapies is needed to inform health professionals, regulatory bodies and consumers.

Introduction

St. John's Wort (SJW) is one of the highest selling herbal therapies: in Germany, prescriptions for SJW comprise 25% of all antidepressant prescriptions1 and in the United States of America annual sales increased from US$20 million to US$200 million between 1995 and 1997.2

Several studies have examined the effectiveness of SJW for treating depression. While evidence remains conflicting, systematic reviews have concluded SJW is more effective than placebo for treatment of mild to moderate forms of depression in the short term.2, 3 Limited long-term data are available4 and the quality of many older trials has been criticised due to use of small, diagnostically heterogeneous sample groups, failure to use standardised rating instruments and inadequate doses of comparison antidepressant medications.3, 5, 6 Recent studies have addressed these methodological flaws. These studies have usually included patients with more severe depression as indicated by depression rating scales.6, 7, 8 A Cochrane review concluded that SJW is of less benefit in this group of patients3 with some randomised controlled trials not showing benefit over placebo for major depression.6, 7 However, one such trial also failed to demonstrate benefit from the comparator antidepressant, sertraline.7 Although reviews have concluded there is insufficient evidence to determine whether SJW is as effective as antidepressant medication,2, 3 recent randomised controlled trials comparing SJW with manufacturer recommended doses of antidepressants found SJW to be as effective as treatment doses of fluoxetine and paroxetine.1, 8 However, these studies did not include placebo groups to establish that this was a treatment effect. Clearly, more research is needed in this area.

SJW has been well-tolerated in trials. Although it can have adverse effects, such as gastrointestinal upset,1, 2 such reports occur significantly less frequently compared with antidepressant medications. Thus, for people suffering mild to moderate depression, SJW may provide an alternative to antidepressant medication with fewer side effects. However, SJW may interact with some prescribed medications, particularly through induction of the cytochrome p450 system.9, 10, 11, 12, 13 These potential interactions with commonly used medications, such as warfarin and the oral contraceptive pill, have considerable implications for health practitioners, regardless of whether they actively encourage use of SJW or not.

Most patients with depression are managed in primary care.14 While general practitioners (GPs) may accept a range of complementary therapies,15 it is not known to what extent they incorporate therapies such as SJW into management of depression, or how much they know about potential complications. Given widespread use of complementary therapies,16 often in combination with pharmaceuticals, it is vital that GPs are aware of such risks, regardless of whether they encourage patients’ use of them. Many patients do not discuss complementary therapy use with GPs, which may put them at risk of harmful interactions. A survey of people taking warfarin found that one-fifth were concurrently using one or more complementary therapies, and of those taking herbal therapies, 92% had not discussed their use with conventional healthcare providers.17

Further complicating matters is ongoing debate about the level of regulation of complementary therapies. Variation from traditional methods of preparation of herbal extracts may impact on the efficacy of the final product.18 A limited number of standardised extracts of SJW have been studied sufficiently in trials to establish effectiveness in mild to moderate depression, yet there is variability in the composition of herbal therapies available to the public.19 Many preparations of SJW sold over the counter do not specify the extract used so consumers cannot be certain they are getting a proven one. For these reasons, the National Institute for Clinical Excellence (NICE) depression guidelines recommend that health professionals educate patients about product variability and risks of SJW, but not prescribe it due to uncertainty about dosage.20

In Australia, debate about regulation was particularly catalysed following the Therapeutic Goods Administration's (TGA) recall of over 1600 complementary medicines from one manufacturer due to inadequate compliance with manufacturing standards.18 In response, an expert committee was established by the Australian government to review many aspects of complementary medicines: regulation of quality, safety and efficacy; consumer information; training of health practitioners; and interactions between prescribed medications and complementary therapies.18 This committee recommended a range of strategies to improve quality of ingredients in complementary therapies listed with the TGA, reporting of adverse events, reliability of information available to consumers and to encourage more quality research into complementary therapies.

It is within this changing climate that this paper reports on a study of Australian GPs’ knowledge and recommendation of SJW for treating mild to moderate depression.

Section snippets

Methods

In 2001, we obtained a random sample of 350 Australian GPs from the Commonwealth Department of Health and Ageing. Exclusion criteria were GPs who were seriously ill, no longer working in general practice or who had left the practice without leaving a forwarding address. We designed a questionnaire to investigate GPs’ management of depression, including questions about knowledge and recommendation of SJW. After pilot testing, the questionnaire was sent to the sample with a covering letter and

Results

Thirty-one GPs were excluded based on the exclusion criteria. Completed questionnaires were returned by 48% (153/319) of the eligible GPs. Respondents were representative of Australian GPs in terms of sex, average age, place of graduation and practice size. However, respondents reported working fewer hours per week than the national average and GPs from remote areas were under-represented (Table 1).21

Discussion

One third of respondents reported recommending SJW to patients for mild to moderate depression. Despite two-thirds reporting some knowledge of SJW, respondents were less knowledgeable about potential side effects and drug interactions of SJW compared with SSRIs. Two-thirds of respondents who recommended SJW did not give detailed dosage instructions. Most GPs obtained information about SJW from general practice journals, while half reported patients as a source of information.

A strength of this

Acknowledgements

We would like to thank the General Practice Education and Training Registrar Scholarship and Research Fund for providing the funding for this research and the general practitioners who participated.

References (31)

  • R. Shelton et al.

    Effectiveness of St John's Wort in major depression: a randomized controlled trial

    JAMA

    (2001)
  • J. Davidson et al.

    Effect of Hypericum perforatum (St. John's Wort) in major depressive disorder: a randomized controlled trial

    JAMA

    (2002)
  • A. Szegedi et al.

    Acute treatment of moderate to severe depression with hypericum extract WS 5570 (St. John's Wort): randomised controlled double blind non-inferiority trial versus paroxetine

    BMJ

    (2005)
  • A. Johne et al.

    Pharmacokinetic interaction of digoxin with an herbal extract from St John's Wort (Hypericum perforatum)

    Clin Pharmacol Ther

    (1999)
  • S. Hall et al.

    The interaction between St. John's Wort and an oral contraceptive

    Clin Pharmacol Ther

    (2003)
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    Funding for this project was provided by the General Practice Education and Training Registrar Scholarship and Research Fund. All researchers are independent of the funding body.

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