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New advice on St John's Wort

  • Published date:
    1 March 2000

The Medicines Control Agency (MCA) announced details today of advice it has received from the Committee on Safety of Medicines (CSM) about the herbal remedy St John's Wort.

There have been recent reports that St John's Wort may prevent some prescription medicines from working properly. The medicines which may be affected by St John's Wort include some medicines for the treatment of HIV infection, some medicines used to treat transplant patients, heart conditions, blood clots,asthma,depression, migraine,and the oral contraceptive pill.

The Department of Health has accepted the advice of the CSM that health care professionals and the public need to be informed of the risks associated with St John's Wort when taken with some prescription medicines. This means that pharmacists and doctors will advise that for those taking the attached list of medicines, St John's Wort should be stopped, although in some cases their dose of licensed medicine may need to be adjusted.

Professor Alasdair Breckenridge, Chair of the CSM said:

New evidence, including studies published in international medical journals, show that St John's Wort may stop some medicines working effectively.

We are advising that anyone who is taking a prescribed medicines should seek the advice of their doctor of pharmacist before taking St John's Wort.

If you are currently taking St John's Wort and some medicinesfor transplant operations, heart conditions, blood clots and asthma,it is important to seek the advice of your pharmacist ordoctorbefore stopping St John's Wort, as the dose of your medicine may need to be changed. If you are taking the oral contraceptive pill or medicines for depression or migraine, you can safely stop St John's Wort. For those taking medicine for HIV infection, stop taking St John's Wort and see your doctor.

"It is important to tell your doctor or pharmacist about any herbal remedy or over the counter medicine you may be taking."

On the CSM's advice, the MCA will be taking action to protect and inform the public, as well as sending detailed advice to all pharmacists and doctors.

The MCA is holding prompt discussions with herbal practitioner organisations and trade associations on the information which should be made available with unlicensed herbal remedies containing St John's Wort, including labelling changes. The MCA will also be updating the patient information of all the licensed medicines most likely to interact with St John's Wort.

Deputy Chief Medical Officer, Dr Pat Troop, said:

St John's Wort when taken alone, and with many drugs, causes no harm. When taken with the drugs listed today, there are health concerns. This is why we are taking this balanced approach between public safety and consumer choice.

The MCA is working with the herbal sector so that we can ensure that the correct information about possible interactions with other medicines is given to members of the public buying products containing St John's Wort.

"As an alternative to contacting their pharmacist or doctor, patients can also telephone NHS Direct on 08 45 46 47, who can advise them on action they may need to take."

Michael McIntyre, Chairman of the European Herbal Practitioners Association, said:

"Herbal practitioners are aware that herbal medicines need to be prescribed and taken with care. They fully support the action being taken today to inform the public of possible interactions between St John's Wort and certain other medicines."

Penny Viner, Director of the Health Food Manufacturers' Association (HFMA), said:

"We agree it is important that the public should be well informed about the need to use St John's Wort with care. The HFMA intends to work closely with the MCA and other trade associations to agree arrangements to give clear information to the public about the possibility of interactions with other medicines. This underlines the need to press ahead in the search to improve regulatory arrangements for herbals.

Notes to Editors

  1. Preparations containing St John's Wort are widely available in this country as herbal remedies exempt from licensing requirements. Exempt herbal remedies are sold in the UK without any written claims. However, St John's Wort is known for its use in treating a number of conditions including low mood and mild to moderate depression.
  2. The new evidence suggests that St John's Wort preparations may interact with some other medicines either by affecting drug metabolism (how drugs are broken down in the body) or by affecting neurotransmitters (brain chemicals).
  3. Under exemptions in Section 12 of the Medicines Act 1968, herbal remedies such as those containing St John's Wort are not subject to the standard controls for licensed medicines. These unlicensed herbal remedies are sold without brand names or any claims. There are currently no statutory requirements that these unlicensed herbal remedies should give specific warning information to the public.
  4. The Committee on Safety of Medicines (CSM) is an independent committee of experts that advises Government on the safety, quality and effectiveness of medicines.
  5. Evidence that St John's Wort reduces the effectiveness of some other medicines comes from studies and from case reports which have been reported directly to the MCA through the Yellow Card Scheme or have come to the MCA's attention through the articles in The Lancet and The British Medical Journal. The evidence has come from a number of different countries.
  6. The Medicines Control Agency (MCA) is currently in dialogue with a wide range of organisations across the natural health sector about the need to improve the regulatory approach to herbal medicines. This would achieve a more effective balance between consumer choice and consumer safety. A key requirement of any new regulatory arrangement will be to provide the consumer with more systematic information about the herbal remedy and its use. The UK is also playing an active role in ongoing European Union discussions about improving the regulatory framework for herbal medicines.
  7. The MCA will be holding prompt discussions with organizations representing herbal practitioners, manufacturers and retailers involved in the herbal remedy trade to ensure that appropriate information is available to the public when they buy unlicensed herbal remedies. Among the organizations which will be involved are the National Institute of Medical Herbalists, the Health Food Manufacturers Association, the British Herbal Medicine Association, the Council for Responsible Nutrition, and the Institute of Health Food Retailing.
  8. The yellow card adverse drug reaction reporting scheme enables health professionals, including doctors and pharmacists to report suspected adverse reactions to medicines to the MCA and CSM. In 1996 the scheme was extended to unlicensed herbal medicines. In November 1999 the scheme was extended to community pharmacists. One of the objectives of this change was to achieve higher reporting levels for herbal medicines.
  9. Medicines which the Committee on Safety of Medicines have advised may interact with St John's Wort:

Medicines: Conditions for which medicine mainlyused:

Warfarin     heart conditions and blood clots

Digoxin    heart conditions and blood clots

Anticonvulsants (carbamazepine, phenobarbitone, phenytoin)epilepsytheophylline

Asthma and chronic bronchitis

Selective Serotonin Reuptake Inhibitors (SSRIs) (citalopram, fluoxetine, fluvoxamine, paroxetine, sertraline) depression   

triptans (sumatriptan, naratriptan, rizatriptan, zolmitriptan) migraine  

Cyclosporin

Following transplantation    indinavir, nelfinavir, ritonavir, saquinavir efavirenz, nevirapine

HIV infection

oral contraceptives

10. A copy of the patient information sent to doctors and pharmacists is attached. A copy of the full information sent to health professionals can be obtained from the MCA website at www.open.gov.uk-mca/mcahome.htm. Non-journalists with further queries can phone the MCA on 0207 273 0000. Journalists with further queries can contact the Department of Health press office on 0207 210 5649.

FACT SHEET FOR THE PUBLIC

Important safety information for people taking St John's Wort preparations St John's Wort (SJW) preparations are unlicensed herbal remedies. Their levels of active ingredients can vary from one preparation to another. They are widely used in the UK being available from pharmacies, health food shops and herbal practitioners. St John's Wort preparations may interfere (interact) with medicines, stopping them from working properly. If you are taking medicines it may not be safe for you to take St John's Wort preparations. The advice in the box is provided below to help you understand how this may affect you.I am currently taking a St John's Wort preparation, and I am not taking any medicine(s).

Advice:If you buy a medicine from a pharmacy or are prescribed a medicine by your doctor you must tell your pharmacist or doctor about the St John's Wort preparation.I am already taking medicine(s) but I would like to start taking a St John's Wort preparation.

Advice: You must not take a St John's Wort preparation until you have checked with your pharmacist or doctor that it is safe for you to do so.

Epilepsy or fits: I am on tablets for epilepsy/fits and I am also taking a St John's Wort preparation,

Transplant: I am on tablets following a transplant and I am also taking a St John's Wort preparation,

Asthma or chronic bronchitis: I am on theophylline tablets for my chest and I am also taking a St John's Wort preparation,

Heart condition: I am taking digoxin for a heart condition and I am also taking a St John's Wort preparation,

Blood clots: I am taking warfarin to thin my blood and I am also taking a St John's Wort preparation,

Advice for patients with any of these conditions: You will need to stop taking the St John's Wort preparation as it may stop your medicine from working properly. However, you should see your pharmacist or doctor before stopping the St John's Wort preparation as the dose of your medicine may need to be altered to prevent side effects.Contraceptive pill: I am on the pill and I am also taking a St John's Wort preparation,

Advice:You should stop taking the St John's Wort preparation as it may stop your pill from working. Continue to take your contraceptive pill as normal. There is no need to see your pharmacist or doctor urgently, however, mention it when younext consult your doctor or are dispensed a medicine.Migraine: I take treatment for migraine and I am also taking a St John's Wort preparation,

Depression: I am on treatment for depression and I am also taking a St John's Wort preparation,.

Advice:You should stop taking the St John's Wort preparation as it may stop your medicine from working. There is no need to see your pharmacist or doctor urgently, however, mention it when younext consult your doctor or are dispensed a medicine.

HIV: I am HIV positive and on treatment and I am also taking a St John's Wort preparation,

Advice: You should stop taking the St John's Wort preparation and see your doctor who may suggest you have your HIV viral load checked.

Advice: I am currently taking both a St John's Wort preparation and a prescribed medicine not mentioned above.

Advice: Tell your pharmacist or doctor that you are taking a St John's Wort preparation when you are next dispensed a medicine or consult your doctor.

  • It is important to always tell your pharmacist or doctor about any herbal remedy or over the counter medicine you are taking.
  • For further information call NHS Direct on 08 45 46 47.
  • Contact:
    Press officer
  • Address:
    Media Centre, Department of Health
    Richmond House, 79 Whitehall
    London
    SW1A 2NL
  • Phone:
    Media Centre
    020 7210 5221

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