The Pharmaceutical Journal
Vol 270 No 7241 p398
22 March 2003

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Same laws of science apply to all medical practices — if only people realised that

By Richard J. Schmidt

The recent correspondence on arnica as a homoeopathic remedy (PJ, 22 February, p268, and 8 March, p330) recycles the same tired old arguments. We can find a way forward, but first we must strip off the emperor's new clothes.

Professor Edzard Ernst has co-authored a report on a study purporting to investigate the efficacy of arnica as a homoeopathic remedy (J R Soc Med 2003;96:60–65). At least two practising homoeopaths have decided that Professor Ernst's output does not sit comfortably with their own understanding of homoeopathy. Professor Ernst, in turn, reveals that he, too, is a trained homoeopath. So, we have a group of three individuals who might reasonably be called peers. Their correspondence is an example of peer review — the touchstone of scientific advancement. But whose views should prevail?

Peer review was (we suppose) carried out on the original bid for funding of the arnica study then again upon submission of the manuscript for publication. So why is there now so much further discussion? Is it because the peer review process has failed, I wonder? The correspondence on arnica as a homoeopathic remedy raises many questions on the subject of peer review, but contributes little to our understanding of homoeopathy.

In its simplest form, a clinical trial investigating the efficacy of a homoeopathic remedy has to include one patient group exposed to the material under investigation and another exposed to a control preparation. We hear from homoeopaths that patients are carefully assessed before a treatment is selected. Kamal Nathwani identified selection criteria for treatment with homoeopathic arnica (PJ, 22 February, p268). Interestingly, these differ from those presented by OnLine Pharmacy on its website. So, assuming that there is actually agreement on how arnica is used in homoeopathy, it should be possible to design a trial of this material in the kind of patients who would be prescribed the remedy by homoeopaths. It would appear that the selection criteria applied in Professor Ernst's study were not those to which Mr Nathwani would subscribe. But they could be considered appropriate by reference to OnLine Pharmacy. Nevertheless, it is hardly surprising that some homoeopathic practitioners are unimpressed by the reported outcome of Professor Ernst's clinical trial. Indeed, they are perfectly entitled to the view that the study design was flawed. After all, from their point of view, this situation is no different from one where an antipsoriatic remedy is being administered to patients presenting with athlete's foot. Meanwhile, an onlooker such as myself wonders whether homoeopaths can even agree on the difference between psoriasis and athlete's foot.

Professor Ernst defends his patient selection criteria by asserting that most homoeopaths use arnica for "acute" rather than "constitutional" prescribing, regardless of the law of similars. So, is it or is it not a homoeopathic remedy? And what is this law of similars that homoeopaths hide behind? Using a process of "reverse engineering" on Mr Nathwani's description of the symptoms he would associate with suitability for treatment with arnica, we can determine that administration of arnica at toxic doses will produce the following symptoms: the sore, lame bruised feeling experienced after traumatic injury; a fear of being touched; a feeling of indifference; a feeling of wanting to be alone; and a fear of pain.

The thing that strikes me most about this list is that all these symptoms are sensations and feelings. My next thought is, how do homoeopaths know that a toxic dose of arnica produces such symptoms? We may safely assume that a formal study of the oral toxicity of arnica in humans has not been carried out in recent times. However, there is some information on this subject in a textbook written in the early 19th century (Pereira's 'Elements of materia medica and therapeutics', 2nd edition, London: Longman, Brown, Green, and Longmans; 1842, pp1354–56): "Jörg and his pupils have submitted themselves to the influence of this plant. From their observations, as well as from the testimony of others, arnica appears to possess acrid properties. When swallowed it causes burning in the throat, nausea, vomiting, gastric pains, and loss of appetite. The active principle becomes absorbed, quickens the pulse and respiration, and promotes diaphoresis and diuresis. Furthermore, it appears to exert a specific influence over the nervous system, causing headache, giddiness and disturbed sleep."

The same text goes on to describe the uses of arnica: "Arnica is indicated in diseases characterized by debility, torpor, and inactivity. It is administered as a stimulant to the general system in various debilitated conditions ... [including] deficient sensibility; ... paralysis; ... asthenic inflammation, &c."

Perhaps a homoeopathic practitioner could enlighten us as to how he or she reconciles Pereira's observations with Samuel Hahnemann's law of similars as regards arnica? The list of symptoms responsive to arnica as provided by Mr Nathwani resembles more closely Pereira's uses of arnica rather than his description of the toxicology of arnica. And if the law of similars does not actually apply in the case of arnica, perhaps homoeopaths should now have another look at other remedies described by Hahnemann in case they too are founded on muddled observations?

The literature clearly describes how tincture of arnica has long been used as a remedy for bruising. Note carefully that it has been used as an application to bruises; there is absolutely no suggestion in this literature that it causes bruising. Therefore, there is no basis under the law of similars to justify the use of homoeopathic arnica as a treatment for bruising. It follows that there is no basis for carrying out a clinical trial to investigate such an effect. J. C. White, a prominent dermatologist at the end of the 19th century, pointed out that tincture of arnica is actually a potent contact allergen and counselled against its use (see 'Dermatitis venenata: an account of the action of external irritants upon the skin. Boston: Cupples & Hurd; 1887). The advice offered was that if patients really wanted to apply arnica to bruises, they should use only homoeopathic concentrations. This advice has evidently been transformed by Chinese whisper to a recommendation for the use of homoeopathic preparations.

This whole sorry tale verges on the farcical and does nothing to enhance the reputation of pharmacists, research scientists or homoeopaths. Why cannot both allopathic and complementary practitioners accept that the same laws of science apply in all paradigms of medical practice?

Contemporary science has demonstrated what GPs and pharmacists have long known: that a patient's state of mind and relationship with his or her health care practitioner both affect therapeutic outcomes. As part of continuing professional development, I would urge all pharmacists involved in the design of clinical trials to explore that literature. I have, and I have observed a burgeoning interest in non-contact therapeutic touch, intercessory prayer, distant healing, etc. SCIRUS (www.scirus.com) is a good place to start. This literature reveals that what we glibly dismiss as "the placebo effect" may be a complex variable that most if not all of our randomised double-blind clinical trials to date have generally failed to take properly into account. Perhaps this is why we always see conflicting outcomes from trials of the same therapy, each one boasting nevertheless "statistical significance"? Perhaps the time has come to direct our scientific endeavours at obtaining a greater understanding of the placebo effect in all of its manifestations. By studying complementary therapies intelligently, we may find ways of enhancing our ability to apply them more effectively.

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