• Complementary medicines can cause unwanted effects as well as beneficial effects.
  • It is important to tell all your healthcare professionals about all the medicines you are taking, including complementary medicines.
  • Ideally, you should discuss the possible benefits and harms of using complementary medicines with your healthcare professionals before you start taking them.
Complementary medicines include vitamin and mineral products, herbal medicines including Chinese and Ayurveda medicines, homeopathic preparations and essential oils. It is important to tell all your healthcare professionals about any complementary medicines you are taking.

The way some complementary medicines are applied or used needs to be considered, because side effects may be caused by the way the medicine is used, rather than the medicine itself. For example, some people who take anticoagulant medicines (blood thinners) after an essential oil massage have reported significant bruising. In this case, it was most likely the massage, rather than the essential oils, that was the cause of the bruising.

Interaction with other medicines

People often think complementary medicines are safe and will not cause any problems. However, complementary medicines may cause side effects or interact with prescription medicines, alcohol and other drugs, and other complementary medicines to cause side effects. It is important to tell all your health care professionals about all the medicines you are taking, including prescribed medicines, over-the-counter medicines and complementary medicines.

Some complementary or alternative medicines can interfere with cancer treatments. If you are about to receive chemotherapy, talk to your oncologist or haematologist about any other therapies or medicines you are taking or thinking of trying. Tell other health professionals (for example, nurses or pharmacists) at your treatment centre before starting treatment if you are taking complementary medicines.

Why people don’t tell their healthcare professionals

About half the people who use complementary medicines do not tell all their healthcare professionals. The reasons include:
  • Not thinking of complementary medicines as ‘medicines’
  • Thinking that products promoted as ‘botanical’ or ‘natural’ are safe and not likely to cause side effects
  • Believing their healthcare professionals are either not interested or will not understand why they use complementary medicines
  • Feeling concerned their healthcare professionals will be judgemental or negative
  • Believing that healthcare professionals have limited knowledge about the effectiveness and potential benefits and harms of complementary medicines
  • Not being asked by their healthcare professionals about complementary medicines.

What you should tell your healthcare professionals

If you don’t tell your healthcare professionals that you are using complementary medicines, you may put your health at risk. You should give your healthcare professionals the following information:
  • The type and name of any complementary medicines you are taking
  • How often you take the medicine and the dose
  • The amount of active ingredient in each dose – it may be easier to bring the medicine with you (you need to use the botanical names of herbal medicines and essential oils to avoid confusion caused by the common names)
  • How long you have been taking the medicine and why you are taking it
  • The health benefits that you expect from taking the medicine
  • Whether the medicine has worked for you.
Make sure you tell your healthcare professionals about any changes to complementary medicines you are taking.

If you’re advised to stop using complementary medicine, ask why

Your healthcare professional may not support you taking the complementary medicine. If they advise you to stop taking it, ask why before you assume that they are biased against complementary medicines. There may be good medical reasons why you should not take a particular complementary medicine, such as when there is an increased risk of interactions with other medicines or side effects.

Complementary medicines are not always ‘natural’ or safer

Many people believe complementary medicines, such as herbal remedies, are safer than other medicines because they come from natural sources. This is not always true. Natural substances still have the potential to be harmful to us. Some complementary medicines, while their original source may be ‘natural’, are manufactured in similar ways to conventional medicines.

Side effects of complementary medicines

Complementary medicines may cause side effects, such as:
  • Echinacea – over 20 different types of side effects have been reported, including asthma attacks, hives, swelling, aching muscles and gastrointestinal upsets.
  • Feverfew – pregnant women are cautioned against using this herb because it can trigger uterine contractions. In animal experiments, feverfew was found to trigger spontaneous abortions (miscarriages).
  • Asteraceae plants (from the daisy family) – include feverfew, Echinacea, dandelion and chamomile. Side effects include allergic dermatitis and hay fever.

Complementary medicines can interact with prescription medicines

Interactions between complementary medicines and prescription medicines can occur. For example, the medicines may have similar active ingredients that act in the same way. The complementary medicine may also either increase or reduce the effectiveness of the prescription medicine.

Some interactions can put people’s health at risk. Examples of interactions include:
  • Echinacea may interact with drugs broken down by the liver.
  • Many complementary medicines – including feverfew, ginkgo and chamomile – may increase the risk of bleeding in people taking anticoagulant medicines such as warfarin and anti-inflammatory medicines such as aspirin.
  • St John’s wort has caused breakthrough bleeding and unwanted pregnancy in women taking the oral contraceptive pill.
  • St John’s wort increases serotonin. Taking St John’s wort at the same time as other medicines that increase serotonin (such as antidepressants) increases the risk of serotonin toxicity (syndrome) – symptoms include tremors, high temperature and low blood pressure and can range from mild to life threatening.

Check with your doctor before using complementary medicines

Talk to your doctor about the benefits and risks of your chosen complementary medicine before you start taking it. It is important that you have a correct diagnosis before you treat any condition, otherwise the benefits of appropriate treatment might be delayed and put your health at risk.

Some people are at greater risk of adverse reactions or complications than others if they use complementary medicines. People at high risk include:
  • Pregnant women, especially in the first trimester
  • People with kidney or liver disorders
  • People who are already taking prescription medicines, non-prescription medicines or other complementary medicines
  • People taking multiple medicines
  • Young children
  • Older people
  • People who are malnourished – for example, people with anorexia
  • People who misuse alcohol or other drugs.

Surgery and tests

If you are scheduled for any medical investigation or surgery, you may need to stop taking your complementary medicines or adjust the doses some time before the procedure is scheduled to take place. You should ask your healthcare professional what to do about all your medicines if you need to have an investigation or surgery.

Choose complementary medicines carefully

It is best not to self-prescribe any medicine, including complementary medicines. Always see a registered practitioner.

If you decide to buy complementary medicines ‘over the counter’, read the labels on all packages and containers. Select products that are manufactured to Australian standards and have an Aust L or Aust R number on the package. This means the medicine meets Australian manufacturing and safety standards and is less likely to be contaminated.

Medicines purchased in other countries or purchased on the Internet may not be manufactured to the same standard.

Where to get help

  • In an emergency, call triple zero (000)
  • Your doctor
  • Nurses, especially specialist nurses such as diabetes educators or cancer nurses
  • Pharmacists
  • Other healthcare professionals, such as complementary therapists
  • Medicines Line Tel. 1300 MEDICINE (1300 633 424) – for information on prescription, over-the-counter and complementary medicines
  • Adverse Medicine Events (AME) Line Tel. 1300 134 237 – to report and discuss possible side effects from your medicine
  • Victorian Poisons Information Centre Tel. 13 11 26 – seven days a week, 24 hours a day – for advice about poisonings, suspected poisonings, bites and stings, mistakes with medicines and poisoning prevention advice.
  • NURSE-ON-CALL Tel. 1300 60 60 24 – for expert health information and advice (24 hours, 7 days)

Things to remember

  • Complementary medicines can cause unwanted effects as well as beneficial effects.
  • It is important to tell all your healthcare professionals about all the medicines you are taking, including complementary medicines.
  • Ideally, you should discuss the possible benefits and harms of using complementary medicines with your healthcare professionals before you start taking them.
  • Complementary and alternative therapies, Cancer Council Victoria. More information here.
  • Robotin MC, Penman AG, ‘Integrating complementary therapies into mainstream cancer care: which way forward?’, Medical Journal of Australia, vol. 185, no. 7, pp. 377–379. More information here.

More information

Complementary and alternative care

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Alternative systems and therapies

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This page has been produced in consultation with and approved by: NPS MEDICINEWISE

Last updated: August 2014

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Content on this website is provided for education and information purposes only. Information about a therapy, service, product or treatment does not imply endorsement and is not intended to replace advice from your doctor or other registered health professional. Content has been prepared for Victorian residents and wider Australian audiences, and was accurate at the time of publication. Readers should note that, over time, currency and completeness of the information may change. All users are urged to always seek advice from a registered health care professional for diagnosis and answers to their medical questions.