Alternative medicine: Safety issues

Last updated: Sunday, July 12, 2015

1. Herbal medicines


Kava can't be sold in the UK for internal use  
Courtesy of Wowbobwow12 via Wikimedia Commons
Many patients perceive herbal medicines as ‘safe’ because they occur naturally. However, some herbal medicines can be potentially harmful at therapeutic doses, e.g. kava kava, now withdrawn from the UK, can cause hepatotoxicity; St John’s wort can interact with many conventional medicines.

In addition, the quality of some unregulated herbal products such as those used in traditional medicine may be causes of harm. Potential sources of problems include:

  • Failure of good manufacturing practice
  • Adulteration (e.g. inclusion of pharmaceuticals or toxic metals)
  • Misidentification of herbs
  • Substitution (i.e. different herb used to that which is supposed to be in the preparation)
  • Varying strengths of active ingredient (e.g. 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 in response to common clinical enquiries, e.g. 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 MHRA through the yellow card reporting scheme.

2. Homeopathic medicines

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 may 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.

3. Dietary supplements

Dietary supplements also have the potential to cause adverse effects and to interact with conventional and alternative medicines. Some products may contain levels of vitamins in excess of those in prescription-only medicines. However, the Food Standards Agency has set safe levels of intake for vitamins and minerals.