St. John’s Wort, known as Hypericum perforatum, is primarily used as an antidepressant. If taking St. John’s Wort, tyramine-containing foods (e.g. aged cheese, cured or aged meats and wines) should be avoided. It is also dvisable to check with a medical practitioner before taking any other medications with St John’s Wort, since it has potentially harmful interactions with antidepressants, birth control pills, blood thinners, heart medications and dextromethorphan (contained in various cold remedies). Few studies have evaluated ithe herbs effectiveness for promoting weight loss. St. John’s Wort and ephedra are the two primary ingredients in herbal phen-fen. The use of St. John’s Wort in combination with ephedera for weight loss is potentially dangerous.
How does St. John’s Wort work?
The mechanism of action of St. John’s Wort is not clearly understood. Some references suggest that it may act like a SSRI (Selective Serotonin Re-uptake Inhibitor) while others suggest that it acts like a MAOI (monoamine oxidase inhibitor).
St. Johns Wort dosage
St. John’s wort is available in capsules, tablets, tinctures, teas, and oil-based skin lotions. Chopped or powdered forms of the dried herb are also available. St. John’s Wort products should be standardized to contain 0.3% hypericin. The usual dose for mild depression and mood disorders is 500–1,050 mg of St. John’s wort extract, three times per day, with meals [1,2,3]. To treat inflammation, as in wounds, burns or hemorrhoids, an oil-based preparation of St. John’s Wort can be applied topically. Length of use should be discussed with a healthcare professional.
St. Johns Wort side effects
Even though St. John’s Wort is a natural remedy, caution is recommended in taking this herb. It is advisable to consult a doctor in the first instance. St. John’s Wort is not recommended for children, or for women who are pregnant or lactating.
St John’s Wort may cause dizziness, fatigue, diarrhea, nausea, dry mouth, increased sun sensitivity and hair loss. It may also limit the effectiveness of certain medications including: antidepressant medicines; birth control pills; cyclosporine; digoxin; indinavir and other medicines used to control HIV infection; irinotecan and other anticancer medicines; and warfarin and other anticoagulants.
St. John’s Wort, taken alone, has a relatively low incidence of side effects compared to prescription antidepressants. An adverse events profile of St. John’s Wort found that, of 14 controlled clinical trials, 7 reported no side effects, 2 had no information, and 5 reported a total of seven mild reactions [4]. Additionally, in 7 trials comparing St. John’s Wort with other antidepressants, the adverse reaction rate for St. John’s Wort was consistently lower than that of the antidepressant drugs with which it was compared.
Patients with a history of manic-depressive illness (bipolar disorder) or a less severe condition known as hypomania, should avoid the use of St. John’s Wort as it may trigger a manic episode [5,6,7,8].
Drug interactions with St John’s Wort
St. John’s Wort stimulates an enzyme called cytochrome P450 3A4 that metabolizes at least 50% of the drugs on the market [9]. As a consequence, St. John’s Wort could potentially interfere with the action of a large number of medications. St. John’s Wort should not be taken by patients on digoxin because the herb may decrease levels of the medication and reduce its effectiveness. St. John’s Wort may interact with monoamine oxidase inhibitor drugs, which are used for depression. St. John’s Wort may reduce the effects of the cholesterol-lowering drug simvastatin.
Certain side effects of antidepressants, such as nausea, dizziness, and confusion, may be amplified when St. John’s Wort is taken in conjunction with these drugs. Other drug interactions have been documented. ‘Adverse interactions have been reported between St John’s Wort and two drugs: indinavir, a protease inhibitor used to treat HIV and cyclosporine, a drug used to reduce the risk of organ transplant rejection. Potentially dangerous changes in drug effects can occur when medications such as cyclosporine (Neoral, Sandimmune), digoxin (Lanoxin, Lanoxicaps) and warfarin (Coumadin) are taken with hypericum extracts. Hypericum extracts can decrease the blood levels of antiretroviral medications that are used in the treatment of HIV infection, thus making these drugs less effective. Recent data show that the plasma levels of the protease inhibitor indinavir (Crixivan) were reduced by more than 50% by hypericum (St. John’s Wort) products.’ – National Institute of Mental Health.
Active constituents of St John’s Wort
The major compounds in St. John’s Wort include hypericin, pseudohypericin, other dianthrones, flavonoids, hyperforin, xanthones and tannins,. Hyperforin is believed to be the major constituent responsible for antidepressant activity, and has been shown to inhibit the uptake of 5-HTP, dopamine, noradrenaline, GABA and glutamate. Hypericin extract contains at least 10 groups of constituents that may contribute to the pharmacological activity of the herb. Hypericin is a napthodianthrone derivative that enters the bloodstream and is not broken down in the liver.