The herb that went underground


Following the controversial decision to ban St John's Wort from over-the-counter sale, perhaps we should take a closer look at this popular anti-depressant. It is estimated that more than 70,000 Irish people a year use St John's Wort. There is anecdotal evidence to suggest that patients are having difficulty in obtaining the herbal remedy since the Irish Medicines Board (IMB) made it prescription-only on January 1st this year. People are travelling to the North to stock up on supplies and are also sourcing the herb through the Internet.

St John's Wort is a wild plant, which flowers around St John's Day, June 24th. Hypericum perforatum is the herb's proper name and its active pharmacological ingredient is thought to be hypericin. It has been used as a herbal medicine for almost 1,900 years.

St John's Wort joins an illustrious roll-call of medicines which have their origins in flowers and plants. Digitalis, an important drug in the treatment of heart failure and irregular heart rhythms, is derived from foxglove. Aspirin started life as a derivative of willow bark. Both of these medicines were further refined by the pharmaceutical industry to produce the modern versions we use today. Drug companies still look to the forests of the world for natural substances with which to manufacture useful drugs.

Proponents of a continued over-the-counter availability of St John's Wort have suggested that the (IMB) decision was influenced by the pharmaceutical industry. According to them, hypericum perforatum was eating into the market for conventional anti-depressant medication. There is no evidence to support this assertion.

The decision can probably be traced to a 1996 scientific paper in the British Medical Journal, which reported firm evidence of St John's Wort's efficacy. The study, by Linde et al, reviewed all available clinical trials and found the herb to be significantly better than placebo in the treatment of mild-to-moderate depression. This was one of the strongest scientifically proven reports of the effectiveness of any herbal product. In effect, St John's Wort became part of conventional medicine and subject to the regulatory framework we associate with modern drugs.

In Germany, St John's Wort is extensively used as a prescription drug. In 1994, German physicians prescribed £26 million worth of preparations containing hypericin. This practice started 10 years previously following plant-based therapeutic studies. There is a strong tradition in Germany for prescribing herbs as part of conventional medicine. The products are easily available and are regulated by a national authority.

All of this makes the current difficulties experienced by St John's Wort users even more difficult to explain. If another EU state can regulate and include herbal medicine within the conventional medical system, why can't we do the same? The answer lies partly with the IMB's quick decision to impose a ban on over-the-counter sales before more conventional supply routes had been established. The regulatory authority will argue, quite correctly, that the recent discovery of important drug interactions between St John's Wort and a wide range of commonly prescribed drugs meant that they had to move decisively in the interests of public safety. Research in the US has found that hypericum can reduce the effectiveness of AIDS drugs. There are also important interactions with medicines used for asthma, bronchitis and heart conditions.

Individual doctors and their support systems must play "catch-up" with the new regulations also. The February edition of MIMS, the doctors' desk-top guide to prescribing, contains no reference to St John's Wort. The Irish College of General Practitioners, through its Continuing Medical Education Scheme, is bringing GPs' knowledge up to date on the drug. Meanwhile, pharmacies need to source hypericum in standardised dose format. All of these educational, supply and availability issues take time to implement. Users of the herb could reasonably look forward to a more streamlined availability within the next couple of months.

Does St John's Wort work? In my opinion it is an effective treatment for mild depression. The medicine seems to have a low incidence of side-effects, which is a definite plus. However, it is not effective in patients with moderate to severe depression. I would caution anyone with a history of severe depressive illness who is maintained on a conventional anti-depressant against changing over to the herbal remedy. St John's Wort should not be used in pregnancy or by breast-feeding women. And never, ever use St John's Wort in combination with a conventional antidepressant.