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** (Please see the warning from the UK Government's Committee on Safety of Medicines, before taking St John's Wort.) **

St John's Wort (Hypericum Perforatum) has been labelled the new Prozac. In Germany it is prescribed to patients at least twice as often as the Prozac type drugs, the selective serotonin re-uptake inhibitor (SSRI) family. St John's Wort works in the same way as SSRIs, by inhibiting re-absorption of the brain chemical serotonin, keeping the natural serotonin around the synapses (junctions between nerve cells by which messages are passed throughout the brain) for longer, thereby producing good feelings. Serotonin is essential for normal, healthy mental wellbeing, & when not enough of it is present, or if it is dispersing too quickly from the areas where it is most needed, a depression often results.

For those currently taking prescription anti-depressants-

If you are taking prescription antidepressants & want to switch to St John's Wort, you must observe certain safeguards-

Do not stop taking prescription antidepressants without proper medical care. The withdrawal effects of stopping them too abruptly can be severe.

Do not take St John's Wort for severe depression or bipolar (manic depressive) illness. Not enough research has been done on St John's Wort in relation to these types of depression.

Do not take St John's Wort while taking mono-amino-oxidase (MAO) inhibitors such as Nardil, Parstelin, or Parnate. It appears that St John's Wort works at least in part as a serotonin re-uptake inhibitor (SRI), & combining an SRI with an MAO inhibitor can produce a dangerous rise in blood pressure. After stopping MAO inhibitors, you should wait four weeks before taking SRIs (prescription or St John's Wort).

The best way to change from SRIs (Prozac, Seroxat, Cipramil, etc) to St John's Wort is not known. If St John's Wort acts as a serotonin uptake inhibitor in the same way as prescription SRIs, then it would appear that gradual introduction of St John's Wort while tapering off the prescription antidepressant would be in order. St John's Wort appears to take longer than prescription antidepressants to reach maximum effect. At the same time, care must be taken not to take too many SRIs, to avoid the medical condition known as Serotonin Syndrome, where the brain has too much serotonin.

It is reported that the benefits of St John's Wort can be felt after taking a 300mg tablet three times daily for a month. It is not a good idea to take any self-prescribed supplements indefinitely, so take a break from the St John's Wort after about 6 months, by which time your serotonin levels may have corrected themselves. If you start to relapse, then start taking it again.

Unlike prescription drugs or generic drugs, herbal preparations are sold in a variety of formulations & methods of extraction. So when buying St John's Wort, you don't know what you're getting. Try to buy a reputable make of St John's Wort, such as Kwai, or Solgar.

Side effects of high doses of St John's Wort may include heightened sensitivity to sunlight, & more rarely stomach irritation, allergic reaction, tiredness & restlessness.

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St John's Wort warning, from the UK Government's Committee on Safety of Medicines

MESSAGE FROM PROFESSOR A BRECKENRIDGE, CHAIRMAN, COMMITTEE ON SAFETY OF MEDICINES. 29 FEBRUARY 2000

Dear Doctor/Pharmacist

IMPORTANT INTERACTIONS BETWEEN ST JOHN'S WORT (HYPERICUM PERFORATUM) PREPARATIONS AND PRESCRIBED MEDICINES

This is to inform you of new evidence of important interactions between St John's Wort (Hypericum perforatum) preparations and certain prescribed medicines leading to loss of therapeutic effect of the prescribed medicines. St John’s Wort (SJW) preparations are unlicensed herbal remedies. Their levels of active ingredients can vary from one preparation to another. They are available from pharmacies, health food shops and herbal practitioners. Because St John’s Wort preparations are so widely available, your patients may be taking them without your knowledge. This letter and the enclosed Fact Sheets summarise the Committee on Safety of Medicines’ (CSM) advice and provide guidance on management of patients.

New evidence suggests that preparations of St John's Wort are inducers of various drug metabolising enzymes. This may result in a reduction in blood levels and therapeutic effect of some medicines metabolised by these enzymes. Because levels of active ingredients can vary from one preparation of St John's Wort to another, and patients may switch between preparations, the degree of induction is likely to vary. It is important to note that when patients stop taking a preparation containing St John’s Wort, blood levels of interacting medicines may rise resulting in toxicity. CSM has advised that St John’s Wort should not be used with the following medicines:
· indinavir
· warfarin
· cyclosporin
· oral contraceptives
· digoxin
· theophylline

Although there is no direct evidence, clinically important interactions are also likely with: · other HIV protease inhibitors (saquinavir, ritonavir, nelfinavir) · HIV non-nucleoside reverse transcriptase inhibitors (efavirenz, nevirapine) · anticonvulsants (phenytoin, carbamazepine, phenobarbitone)

Furthermore, St John’s Wort preparations affect neurotransmitters in the brain and may interact with psychotropic medicines including Selective Serotonin Reuptake Inhibitors (SSRIs). St John’s Wort preparations may also have pharmacodynamic interactions with triptans used to treat migraine. These interactions may result in serious adverse reactions.

Patients already taking these prescribed medicines should not take St John’s Wort. Doctors and pharmacists are advised to ask patients about use of non-prescription medicines including herbal remedies. Specific advice on dealing with the interactions listed above is given in Table 1 of the attached Fact Sheet. Please note that the action of many other drugs depends on their rate of metabolism and thus other drugs may also interact with St John’s Wort preparations. St John’s Wort preparations are unlikely to interact with topical medicines with limited systemic absorption and non-psychotropic medicines which are excreted renally.

Suspected interactions with St John’s Wort preparations should be reported to the Medicines Control Agency/Committee on Safety of Medicines through the Yellow Card Scheme. Professor A Breckenridge Chairman, Committee on Safety of Medicines

FACT SHEET FOR HEALTH CARE PROFESSIONALS

Why do SJW preparations interact with other medicines? New evidence suggests that SJW preparations may interact with medicines, either by affecting drug metabolism or levels of neurotransmitters. Drug metabolism may be affected by SJW preparations inducing certain cytochrome P450 isoenzymes in the liver (CYP 3A4, 1A2 and 2C9), as well as, P-glycoprotein. Pharmacodynamic (additive or potentiating) interactions may occur through the effects of SJW preparations on neurotransmitters in the brain (SJW may increase serotonin levels through weak monoamine oxidase inhibiting (MAOI) activity and serotonin re-uptake inhibition).

What is the clinical significance of these interactions? Induction of drug metabolism increases the breakdown of drugs so reducing their blood levels and therapeutic effects. Because the levels of active ingrediants can vary between preparations of SJW and patients may switch between preparations, the degree of induction is likely to change over time. When patients stop taking SJW preparations, blood levels of interacting medicines may rise, leading to toxicity.

Pharmacodynamic (additive or potentiating) interactions may occur with psychoactive medicines including Selective Serotonin Reuptake Inhibitors (SSRIs). St John’s Wort preparations may also have pharmacodynamic interactions with triptans used to treat migraine. These interactions may result in serious adverse reactions.

Which medicines interact with SJW? Table 1 lists medicines where in-vitro studies, pharmacokinetic studies or spontaneously reported suspected adverse reactions demonstrate clinically important interactions. In addition, other drugs are included where evidence is lacking but clinically important interactions are likely. Please note that the action of many other drugs depends on their rate of metabolism and thus other drugs may also interact with SJW preparations. In general, the following medicines are not likely to interact with SJW preparations: · topical medicines with limited systemic absorption (inhalers, creams, ointments, eye and ear drops, enemas etc). · Non-psychotropic medicines which are renally excreted.

 

-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 you next 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 you next consult your doctor or are dispensed a medicine

- 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.