St. John's wort is an aromatic perennial herb that produces star-shaped golden yellow flower with five petals that secrete a red liquid when pinched. Originally, St. John's wort was native to Europe only, but now it can be found growing almost everywhere in the world.
This plant has been used for over 2,000 years. Ancient Greeks believed that its odor repelled evil spirits. Early Christians named the plant in honor of St. John the Baptist because they believed it released its blood-red oil on the 29th of August, the day the saint was beheaded.
Clinical trials support the assertion that St. John's wort is effective in maintaining normal sleep patterns and a healthy nervous system. It is also useful in the release of stress and frustration and in the re-balancing of moods. The efficacy of St. John's wort may be attributed to its effect on the immune system in addition to the effect of its active compounds.
For many North Americans, it is simply amazing that a common ground covering plant like St. John's Wort could present an effective antidepressant option. Its very low incidence of troublesome side effects is all the more wonderful. As a plant, many different chemicals are present, providing a variable "pharmacy" of constituents that work together to synergize an overall neurotransmitter rebalancing, which is the general pharmaceutical approach to treating depression.
In one study, St. John's Wort was effective in 81.8% of patients evaluated for clinical mild to moderate depression, compared to 62.5% treated with Imipramine.(19) The overall accomplishment of St John's Wort for mild to moderate clinical depression is considered to be comparable to standard drug therapy with a considerably reduced report of adverse side effects. In general, it produces improvements in mood with a sense of well-being, and clinical improvement in feelings of sadness, hopelessness, helplessness, worthlessness, sleep initiation, and psychological anxiety, with headaches and fatigue occurring significantly less frequently. St. John's Wort may provide relief for those who suffer seasonal-related depression, and might address PMS-related depression.(20)
In a study in older volunteers, the proportion of REM sleep in the total sleep period was within the normal range of 20%, and after several weeks of treatment, St John's Wort at 300mg TID had no effect on sleep latency or the amount of REM sleep.(21)
In one study, moderate use of alcohol concurrent with treatment did not evidence an adverse interaction and the ability to drive in traffic, concurrent with St John's Wort therapy, was not impaired.(22)
St John's Wort may increase anxiety.(8) St John's Wort may have the ability in the susceptible to induce serotonin syndrome, a condition consisting of extreme anxiety, confusion, nausea, hypertension, and tachycardia.(9)
St John's Wort may in some depressed people precipitate hypomania, mania, or an increased cycling of mood states, particularly people with occult bipolar disorder.(10)
Patients with uncontrolled high blood pressure, angina, or heart failure, should discuss with their physician the potential risk of a tyramine interaction with St John's Wort since it is thought to be a weak MAO inhibiter. Use caution with prescription drugs that are contraindicated with synthetic pharmaceutical MAO inhibitors, including L-dopa, 5-hydroxytryptophane, amphetamines, and over-thecounter cold and decongestion medication containing pseudoephedrine.
Hypericin is a phototoxic constituent in St John's Wort that is known to cause sunburn in animals grazing on St John's Wort. However, in the standardized extract with 0.3 percent hypericin, the recommended dose of 900 mg [300 mg TID] would deliver 2.7 mg of hypericin.
In steady-state oral administration tests running 7 days, 2.7 mg per day of hypericin did not provide evidence for a phototoxic potential in humans.(11) Insufficient data exists to support the use of St. John's Wort during pregnancy or during breast feeding.(12) Hypericin produces singlet oxygen and other excited state intermediates in vitro that indicate it should be a very efficient phototoxic agent in the eye lens. In a study on calf lens, hypericin did not damage lens protein in the dark, but under light conditions produced photo-polymerization.(13) Damage to alpha-crystallin could undermine the integrity of the lens directly by protein denaturation.
Those who are at risk of or have cataracts should supplement their diet with vitamins C and E, as well as lipoic acid, which are known to reduce the risk of cataracts. Another potent natural agent for combating cataract formation is lutein, which is specifically concentrated in the eye lens and the macula for preventing photon induced oxidation.
The American Society of Anesthesiologists caution that St John' Wort, as well as members of the ginseng group, can cause adverse interactions with anesthetics and should be discontinued at least one week before surgery. Cardiovascular collapse during anesthesia has been described in one otherwise healthy patient who had a 6-months history of using St John's Wort prior to surgery.(14)
St John's Wort should not be used with any other antidepressant medication, unless guided by a physician. The effect can be additive and the full outcome is unknown.
St. John's Wort is understood to present only a weak monoamine oxidase inhibition.(15,16) The risk of interaction with tyramine is probably quite low. However, in at least one reported case, St John's Wort is suspected of interacting with tyramine in an incident of hypertensive crisis following consumption of foods containing tyramine.(17)
At the recommended daily amount of St. John's Wort, a blanket fear of a dietary tyramine interaction seems unwarranted. Interestingly, the long and widespread use in Germany and Europe of St John's Wort, where tyramine foods abound, has not given rise to a notable practical problem of tyramine interaction.(4)
Interactions In General:
Since St John's Wort first gained public awareness, numerous herbdrug interactions have been observed or suspected, frequently including cytochrome P450 interactions. The reader is referred to the Natural Medicines Comprehensive Database for interaction details and references.(18)
Side effects with St John's Wort are low in research literature and its extensive use in Germany has not resulted in published reports about serious drug interactions or toxicity after overdose.(4)
In a study with 3,250 patients, the most commonly noted side effects were gastrointestinal symptoms (0.6%), allergic reaction (0.5%), and fatigue (0.4%).(5)
Reports from other clinical studies include dizziness, nausea, restlessness, and dry mouth. Some older patients have complained of mild insomnia at 300 mg three times a day. Dosage reductions may be appropriate in some cases.(6)
The stressful sexual dysfunctions so frequently associated with all synthetic pharmaceutical antidepressants are much less frequently reported with St John's Wort.(7)