A closer look at St. John's Wort

Originally published in the Ottawa Citizen, May 12, 2004
Original Title: All smiles: worts and all

Known as Fuga Demonum or Devil’s Scourge, its original use was to ward off evil spirits and prevent demonic possession. Sixth century Gaelic legend makes reference to St. Columba who carried a piece of the flowering plant in deference to St. John the Baptist around whose birthday the flower would bloom.

Hypericum perforatum or St. John’s wort (wort is the old English term for plant) is used by many to treat depression, anxiety, inflammatory disorders, viral infections and for wound healing.

Several chemical compounds within St. John’s wort do have medicinal properties: the hypericin family, the flavonoids, hyperforin (related to hop bitters), some amino acids and tannins. Indeed, any natural plant extract contains a plethora of biochemical and pharmacological ingredients that can and do interact with different body functions and biochemical processes.

Many double blind placebo-controlled studies indicate that St. John’s wort is effective for mild to moderate clinical depression. It seems to provide benefits similar to serotonin reuptake inhibitors (SSRIs) like fluoxetine (Prozac) and low dose tricyclic antidepressants and was much better than placebo. Most of the studies used a specific plant extract called LI 160 rather than the whole herb.

St. John’s wort is ineffective for people suffering from severe forms of depression that usually require hospitalization. Prescription anti-depressant medications do far better than St. John’s wort under these circumstances.

Hypericin and hyperfolin were originally thought to be the main ingredients that combat depression. Studies seem to indicate that this may not be the case. These two compounds are useful quality control markers with respect to the manufactured product.

Indeed, it seems that when hypericin and hyperfolin are extracted for study, other unidentified chemical compounds come along for the ride. It is these compounds that may be responsible for the antidepressant effect.

There is no evidence to support St. John’s wort for the treatment of anxiety, human immunodeficiency virus (HIV), premenstrual disorder, chronic pain, insomnia and menopausal symptoms. With respect to HIV, the herb can interfere with the actions of certain medical therapies and make the condition worse.

As with any medication, drug interactions and side effects can occur. St. John’s wort does affect the liver’s capacity to metabolize certain drugs. There is a particular liver enzyme pathway called the cytochrome P450 system; one of the most important liver mechanisms to detoxify chemical agents and drugs.

The cytochrome P450 system can be induced (accelerated). This will cause the rapid breakdown of medications and reducing their therapeutic effect. If the cytochrome P450 system is shut down or slowed, the liver is unable to clear out the medication in a timely manner; standard medication dosing schedules can lead overdose and toxic side effects. St. John’s wort induces the P450 system.

St. John’s wort can reduce the efficacy of many medications; the list is too long for this column. Some of the more common drugs affected are the heart medication digoxin, the cholesterol-lowering agent simvastatin (Zocor) and anticoagulant or blood thinner warfarin (Coumadin).

It can interfere with the metabolism of birth control pill causing bleeding or spotting between periods, irregular menstrual bleeding and increase the risk of pregnancy. These side effects occur because the liver eliminates the pill’s hormones within at a faster rate. Indeed, it is recommended that an additional birth control method be used when taking St. John’s wort.

Concomitant use of St. John’s wort with SSRIs like paroxetine (Paxil) and sertraline (Zoloft) can result in excess levels of serotonin causing among other symptoms, agitation, hyperthermia, sweating and rapid heart rate. This “serotonergic syndrome” is a medical emergency.

It can also cause itchy red irritating rashes with skin sun exposure (photodermatitis). This reaction occurs with doses of two to four grams (2000 to 4000 milligrams) of St. John’s wort extract.

It is not recommended for use in pregnancy because it may stimulate contractions of the uterus. Its safety while breastfeeding has not been established.

People suffering from bipolar disorder should avoid using it because it can stimulate a hypomanic or manic episode.

An excellent independent testing organization called Consumer Labs (www.comsumerlabs.org) recently released a review of St. John’s wort products. Six of the ten brands tested for quality control failed.

Three of the products exceeded “the cadmium limit established for medicinal plants by the World Health Organization by 100 to 1000 per cent” and one of the three exceeded the State of California lead limit. Although the cadmium levels would not pose a serious health risk on their own, it is best to avoid this heavy metal because of the small safety margin. Cadmium is a carcinogen and kidney toxin.

The usual dose is 300 milligrams three times per day standardized to 0.3 per cent hypericin. Although effective for mild to moderate clinical depression, consult your pharmacist and doctor prior to using St. John’s wort.

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