St John's Wort

What is St John’s Wort?

St John’s Wort is a herbal remedy which has been known for thousands of years, but has recently been produced in tablet form and extensively marketed as a treatment for depression. Many people are under the impression that as herbal remedies are ‘natural’, this means that they are completely safe and free of side effects. This is not the case: many herbs are very poisonous (hemlock is an obvious example), while other plants are poisonous in some parts and safe in others (e.g. the potato). Extracts from poisonous plants may make very useful medicines when used in the right way (e.g. digitalis, a heart drug which comes from foxglove). And of course there are some herbs that are both harmless and useful as medicines.

St John’s Wort is a plant named after St John the Baptist, whose feast day, June 24 ^th, occurs when
daylight in Europe is longest and the plant is in full bloom. Its five yellow petals resemble a halo, and its red sap symbolises the blood of the martyred saint. The name Hypericum comes from the Greek, meaning ‘greatest health’.

St John’s Wort has been known used as a folk medicine for many hundreds of years, particularly for healing wounds. Its antibacterial properties were reported scientifically in 1959 and 1971, when the active antibacterial substance, called hyperforin, was extracted and analysed. In medieval times St John’s Wort was used for ‘driving out the inner devil’. Paracelcus (c1525) recommended it for hallucinations and ‘dragons’, as well as for healing wounds.

Tablets made from a standardised extract of St John’s Wort have been extensively researched in Germany since the early 1980s, and in recent years it has come on to the market as a herbal remedy, available from health food shops, to be used for mild to moderate depression. It was not found helpful for severe depression, and this was confirmed in more recent reports in America.

Scientific studies of the herb suggest that it acts to increase the activity and prolong the action of the neurotransmitters serotonin and noradrenaline, in a similar manner to standard antidepressants, but with many fewer reported side effects.

The German trials appear to have used a daily dose of total extract, ranging from 0.4 mg (400 micrograms) up to 1000 mg (1 g). Currently the recommended daily dose is about 900 mg of total extract.

As with other antidepressants, St John’s Wort may take two to four weeks to begin to take effect.

There is also a product available combining St John’s Wort with other herbs as Hypericum Complex. This contains lemon balm (Melissa officianalis) and hops (Humulus lupulus) which are both sleep-inducing herbs. The complex is therefore suggested for people with depression who have difficulty sleeping.

Is it always safe to take St John’s Wort?

There are no listed contraindications for St John’s Wort (situations when it should not be used). It should be used with caution during pregnancy and while breast-feeding because there is no information on its safety in these conditions. Patients with a diagnosis of manic depression should use it with caution, since, as with all antidepressants, its use is associated with ‘switching’, or moving rapidly from a low to a high mood.

Is it safe to take St John’s Wort with other drugs?

St John's wort has significant interactions with a large number of prescribed medicines which are in common use, in addition to those mentioned below. These are listed in the British National Formulary (BNF). People who are taking any other medicine should always seek professional advice from a doctor or a pharmacist before combining it with St John’s Wort.

You should not take St John’s Wort at the same time as SSRI or MAOI antidepressants. (It has been made a prescription-only drug in the Irish Republic because of anxieties about its possible similarity to MAOI antidepressants.)

St John’s Wort may prolong the effects of some sleeping pills and anaesthetics. If you are to receive an anaesthetic you should tell the anaesthetist if you are taking St John’s Wort.

It also reduces blood levels of oral contraceptives , increasing the risk of pregnancy and breakthrough bleeding.

Are there any side effects?

The most commonly reported side effects include gastrointestinal symptoms (such as nausea, vomiting, diarrhoea), allergic reactions, fatigue, dizziness, confusion, and dry mouth in a small percentage of patients. Another rare side effect is photo-sensitisation – increased sensitivity to sunlight. This is associated with high doses, but people taking it should increase their sun protection and avoid strong sunlight.

This text taken from http://www.mind.org.uk/