Herbal and Homeopathic Medicines
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Alternative Medicine 12. Alternative Medicine Introduction Complementary and alternative medicine (CAM) is a broad term that includes herbal products, nutritional supplements, homeopathic medicines, aromatherapy oils and many other beliefs, therapies and practices (eg yoga, massage). In this Tutorial, we shall concentrate on dietary supplements, and herbal and homeopathic medicines. Alternative medicine is perceived to be ‘safe’ by the general public despite a lack of good- quality evidence to support its efficacy and tolerability. Although some studies have recently been published on the use of selected preparations such as St John’ Wort for depression, and glucosamine for bone and joint disorders, for most alternative medicines there remains a lack of good quality research-based information. General Principles 1. Herbal Medicine Herbalists use plant-derived medicines at doses where true pharmacological effects can occur and can be measured. This is in contrast to homeopathic medicine (see below). Modern herbalists use plants largely via a symptom-based approach to diagnosis. 2. Homeopathic Medicine The two main principles of homeopathic medicine are that 1. ‘Like cures like’ – that is that a patient’s symptoms are treated with a medicine that causes the same effects. For example, oral consumption of herbal Arnica montana in significant quantities can cause a reduction in platelet aggregation, which could increase bruising. However homoeopathic doses of Arnica are used to prevent or treat bruising. 2. The more dilute a preparation, the more potent it is. Plants yield most of the original ingredients in homeopathic medicines. The first step is to prepare a mother tincture with alcohol. Then the tincture undergoes repeated dilution followed by vigorous shaking (succussing). Two systems of dilution exist for homeopathic remedies: 1. Decimal system is known as ‘x’. These are 1 in 10 dilutions, or a concentration of 1x10-1 eg one part of mother tincture with nine parts of solvent (water or alcohol) = 1x. Then take one part of resulting solution and mix with nine parts of solvent (water or alcohol) = 2x. 2. Centesimal system is known as ‘c’. These are 1 in 100 dilutions or a concentration of 1x10-2 eg one part of mother tincture with 99 parts of solvent (water or alcohol) = 1c. A range of strengths are available over-the-counter, but strength 6c is common. It is worth noting that dilutions of more than 12c or 24x are unlikely to contain any molecules of the active ingredients. 12.1 Version 4 2006 Alternative Medicine 3. Dietary Supplements In the UK, dietary supplements are defined as ‘foods’ in unit dosage form (eg tablets, capsules, elixirs) taken to supplement the diet. Most are products containing nutrients normally present in foods. They are used by the body to develop cells, bone, muscle etc., to replace co-enzymes depleted by infection and illness, and to generally maintain good health. In addition to vitamins and minerals, this definition also includes supplements such as garlic and evening primrose oil. Regulation 1. Herbal Medicine The regulation of herbal medicines is complicated. Currently there are three classes: 1. Licensed Herbal Medicines: have a marketing authorisation issued by the Medicines and Healthcare products Regulatory Agency (MHRA). New licences have to meet safety, quality and efficacy criteria in a similar manner to conventional licensed medicines. 2. Unlicensed herbal medicines: these products don’t have to meet specific standards of safety and quality and so standards can vary widely. 3. Registered traditional herbal medicines: A registration scheme for traditional herbal medicines began in 2005 although there is a 7 year transitional period, so it may take some time for registered medicines to appear on the market. Go to the MHRA website for more information. There are other forms of regulation which restrict use of certain plant species, and some products containing plants are marketed as dietary supplements (see below). Currently, there is no statutory regulation of herbalists in the UK. 2. Homeopathic Medicine Homeopathy is practised by two separate groups: 1. Medical homeopaths are medically qualified practitioners regulated by the General Medical Council. 2. Non-medical homeopaths are professionals who use homeopathy only. They are represented by at least four main bodies (eg Society of Homeopaths). Homeopathic manufacture is controlled by the Medicines Act 1968. With few exceptions, no medical claim can be made for a homeopathic remedy and they can only be promoted generically. 3. Dietary Supplements In the UK, the majority of dietary supplements are legally classified as foods, and as such are sold under food law. The exceptions include some branded products (eg Maxepa, Pregaday) and some generic vitamin and mineral preparations, which are classed as licensed medicines. Supplements that fall under food law do not have to undergo the same rigorous clinical testing as conventional medicines. Dietary supplements are not allowed to make medicinal claims but can make health claims. For more information refer to Further Reading (Mason – Dietary Supplements). 12.2 Version 4 2006 Alternative Medicine Safety Issues 1. Herbal Medicine Many patients perceive herbal medicines as ‘safe’ because they occur naturally. However, some herbal medicines can be potentially dangerous, at therapeutic doses, eg kava kava, now withdrawn from UK, can cause hepatotoxicity; St John’s wort can interact with many conventional medicines. In addition, there is no standardisation at present for herbal medicines. Therefore potential sources of problems include: – Failure of good manufacturing practice. – Adulteration (eg inclusion of toxic metals or conventional pharmaceuticals). – Misidentification of herbs. – Substitution (ie different herb used to that which is supposed to be in the preparation). – Varying strengths of active ingredient (eg for St. John’s Wort preparations). – Incomplete labelling. – Incorrect dosage or instructions. The amount of information available about herbal medicines is very limited. This lack of data makes it difficult to provide information about common enquiries, eg drug-herbal interactions, adverse effects and use in special patient groups. In order to answer questions about interactions involving conventional medicines and herbal products it is necessary to exercise some lateral thinking, since there are rarely any systematic or high quality studies. It is helpful to look for herbal side effects that might be additive to those of the medicine or, conversely, may oppose its therapeutic action. As the use of herbal medicines increases, the risk of adverse reactions will increase. Currently, the main method for reporting adverse reactions due to herbal medicines in the United Kingdom is to the Committee on Safety of Medicines (CSM) through the yellow card reporting scheme. MI pharmacists should encourage reporting of herbal side effects to the CSM. 2. Homeopathic Medicine Homeopathic medicines are designed to be used for self-limiting conditions only. Patients should be discouraged from repeatedly self-treating the same condition without medical advice. There is very limited information about adverse effects of homeopathic remedies, although in theory these are most unlikely to exist. In about 10% of patients with chronic conditions, their illness may be aggravated within 2-5 days of taking a remedy. If this occurs, the patient may be advised by their homeopath to stop taking the remedy until symptoms subside. The remedy should then be recommenced at a lower frequency or lower potency. There is no evidence that homeopathic medicines interact with conventional medications. In practice, if a homeopathic medicine is from a reputable source and the strength is stated, it is generally accepted that no interaction with conventional medicines, or any adverse effects, based on conventional beliefs would be anticipated. High concentration or unknown dilution products may, theoretically, contain active ingredient and could potentially interact with conventional medicines. Such situations should be treated as if dealing with a herbal product. 12.3 Version 4 2006 Alternative Medicine 3. Dietary Supplements Dietary supplements also have the potential to cause adverse effects and to interact with conventional and alternative medicines. Dietary supplements containing levels of vitamins in excess of those in prescription-only medicines are available to the public. However, the Department of Health is setting maximum limits of intake for vitamins and minerals to reduce the use of these ‘mega- dose’ products (eg vitamin B6). Questions to Ask an Enquirer Is the patient already taking the alternative medicine or do they want to start taking it? Identify the alternative medicine, indication, route, strength, dose and frequency. If applicable, how long has it been taken for? Has the patient self-diagnosed the condition that they are seeking to treat? If they have, perhaps they should consider speaking to a healthcare professional first. Does the patient take any conventional medication? Is there any history of adverse drug reactions or allergies? Check relevant past and present medical history. Example Sources to Use in Answering Enquiries The sources used to answer alternative medicine enquiries will depend on the nature of the enquiry (eg interactions, adverse effects, general reviews). AltMedex (http://www.thomsonhc.com/home/dispatch) – part of the Micromedex Series (subscription