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Herbal Interactions With Cardiac Drugs  (Arch IM  Mar. 27, 2000;160  ) Tsung O. Cheng, MD; Robert M. Feingold, MD

Herb-Drug Interactions (Lancet Jan. 2000, 355:134)  Adriane Fugh-Berman

St. John's Wort  

Hypericum extract (St John's wort) improves depression and quality of life  
In the first comparative three arm trial of  Hypericum perforatum (St John's wort) 350 mg tid over eight weeks, Philipp et al (p 1534) showed that the standardised extract STEI 300 was a more effective antidepressant than placebo and at least as effective as imipramine (100 mg daily) in a sample of 263 patients in Germany with moderate depression. Quality of life was improved with the hypericum extract compared with placebo in both mental and physical components of the SF-36. Phytomedicine is therefore an important alternative to tricyclics in patients with moderate depression.
(BMJ Dec.11,1999;319:1534 - Michael Philipp)

American Ginseng (Panax quinquefolius L) 3 g capsules Reduces Postprandial Glycemia in Nondiabetic Subjects and Subjects With Type 2 Diabetes Mellitus  - Vladimir Vuksan, PhD, etc.  (Arch IM April 10, 2000;160:1009 )
Reductions in area under the glycemic curve were 18% +/-31% for nondiabetic subjects and 19 +/-22% and 22 +/-17% for subjects with type 2 diabetes mellitus administered before or together with the glucose challenge, respectively.

Some Herbs may be Harmful under Certain Conditions

The top-selling herbs in the United States are echinacea, ginseng, ginkgo, saw palmetto, garlic, evening primrose oil, St. John's wort, kava-kava, feverfew, and milk thistle.5 These have been found to be relatively safe, but some carry warnings and should be used only with caution by patients who are pregnant or nursing as well as by those with a history of hypertension. Herbs whose use requires caution include ma huang, chaparral, comfrey, yohimbine, lobelia, and germander. The FDA suggests that these herbs may cause serious adverse reactions.6,7

Ma huang (also known as ephedra or ephedrine)
has had recent fame by being marketed with St. John's wort as "herbal fen-phen."8 Because this herb may cause high blood pressure, rapid heart rate, nerve and muscle damage, stroke, and memory loss, its use is not recommended.

is a desert shrub that has been marketed as a dietary antioxidant supplement. However, this herb has been associated with severe liver toxicity and should not be used.9,10

is popular in some health stores as a remedy for cancer and ulcers. Like chaparral, comfrey has been associated with liver toxicity.9

taken by male patients to relieve impotency or achieve an erection is also available in prescription form. However, yohimbine has been associated with kidney failure, seizures, and even death, so patients should avoid yohimbine unless they take it under the direct supervision of a physician. Yohimbine is contraindicated in pregnant women or individuals with a history of renal insufficiency.9

Lobelia (also known as Indian tobacco)
can produce sensations similar to those experienced with nicotine and has been associated with swelling of the lower extremities, tachycardia, hypotension, and coma.

like ma huang, has also been marketed for weight control. The main side effect associated with this herb is liver toxicity.

As shown above, many herbs used medicinally can have serious, life-threatening side effects. Of particular concern are those that may cause irreversible liver failure, which can result in death.10-13 For these reasons, I recommend that physicians review carefully with their patients the possible side effects of herbs before advising their use. In general, herbs should not be prescribed to patients who are (or who are planning to become) pregnant, nursing mothers, infants, or who have any documented allergies to plants.

Beneficial Herbs That Can Complement Medical Treatment

Echinacea (Echinacea angustifolia, Echinacea purpurea) has been evaluated extensively,14 and many patients use this herb to prevent colds and other infections because it appears to boost the immune system and has shown activity against viruses, bacteria, and fungi. However, having heard that a major problem facing our medical establishment is the number of bacteria that have become resistant to antibiotics, some patients try echinacea themselves as first-line therapy for respiratory tract infections because they want to avoid long-term exposure to antibiotics. Without receiving available medical advice, these patients may thus be unaware of the side effects associated with Echinacea. These side effects may include fever, chills, nausea, and vomiting. Because of its potential to stimulate the immune system, Echinacea should not be used by patients with a history of multiple sclerosis, AIDS, tuberculosis, or other autoimmune diseases, and no patient should take this herb for longer than 6-8 weeks.14

Saw palmetto (Serenoa repens)
has been widely used in Germany to treat benign prostatic hypertrophy. Extracts of this herb containing fatty acids and sterols may have antiandrogenic activity.15 Saw palmetto is relatively safe and has few side effects. Nonetheless, patients taking this herb should schedule routine appointments with their health care provider to allow appropriate long-term management of symptoms associated with prostate enlargement and to follow clinical guidelines for screening prostate cancer.

taken primarily to increase stamina and endurance, is relatively safe and may help in treating hypertension. Nonetheless, blood pressure should be monitored during its use.

Ginkgo biloba,
is an interesting herb: The ginkgo is the sole survivor of the family Ginkgoacea and can be dated back almost 200 million years.16 The herb Ginkgo biloba is used by many patients to manage tinnitus and to prevent age-related memory loss.16-20 It is the most widely prescribed phytomedicine worldwide. This wide popularity arises from studies which suggest that Ginkgo biloba can slow the deteriorating effects of dementia.18 High concentrations of the herb's active ingredients enter the brain's circulation and apparently improve blood supply to nerve cells.17 Side effects associated with use of Ginkgo biloba include dyspepsia, headache, and allergic skin reactions. In addition, because of its anticoagulant properties, use of this herb should be discontinued before surgery:  Spontaneous bilateral subdural hematoma has been reported in patients taking ginkgo biloba for prolonged periods of time.21

Garlic (Allium sativum)
has been used by patients because of reports suggesting that it has antibacterial, antifungal, anticoagulant, lipid-lowering, and vasodilative properties.22 Combined, the latter three properties may improve circulation to the heart and brain by preventing formation of blood clots, closure of blood vessels, and cholesterol deposits.23 For this reason, garlic should be avoided before elective surgery.24

Evening primrose oil
has multiple beneficial properties. It is a good source of gamma linoleic acid (GLA), which promotes prostaglandin formation (helpful in reducing painful inflammation in arthritis).

Glucosamine sulfate
is a chemical which naturally occurs in the body but may be deficient in some arthritic joints. It is therefore used by many patients to treat osteoarthritis. The main function of glucosamine sulfate is to stimulate production of glycosaminoglycans, a major structural component of cartilage. Some studies have shown that glucosamine sulfate helps to relieve pain and inflammation in osteoarthritis.25,26 The mechanism is not well known but may involve providing the natural substances needed to allow arthritic joints to heal.

Feverfew (Tanacetum parthenium)
is an herb that may be useful for treating migraine headaches.27 The plant contains a compound called parthenolide,28 which is thought to prevent secretion of neurochemicals associated with vascular headache.  Feverfew has been associated with mouth ulceration and contact dermatitis and is contraindicated in pregnancy.

Herbs which have important activity in the gastrointestinal tract include milk thistle (Silybum marianum), chamomile (active against pyrosis and intestinal spasm), and ginger (Zingiber officinale) (used to treat nausea and motion sickness). Milk thistle has been used for centuries to treat liver disease, but gastroenterologists are today noting many patients taking this herb. Milk thistle may be very helpful in treating various liver conditions and in protecting the liver from injury after exposure to toxins such as alcohol, chemical solvents, and poisonous mushrooms.31 Peppermint is an herb that has been used to treat symptoms of irritable bowel syndrome as well as spasm of the common bile duct.32 Oils of peppermint--often used in chewing gum--may relax smooth muscles that prevent physiologic spasm of the common bile duct and the lower esophageal sphincter. For this reason, patients should avoid products containing peppermint oil extract or peppermint oil if they have a history of gastroesophageal reflux disease or gallstones.

In Europe, many different herbs are used to manage anxiety and depression. Some of the most popular and safest include kava-kava for treating anxiety and St. John's wort for treating depression. When compared with other antidepressant agents in controlled studies, St. John's wort was found to effectively treat mild forms of depression at a third the cost with only a third as many side effects as standard treatment.33 Because this herb is pharmacologically similar to monoamine oxidase inhibitors, hypertensive patients who use St. John's wort should avoid foods that contain tyramine and other medications (eg, sympathetic amines and serotonergic agents) that may react with monoamine oxidase inhibitors.34,35

Some women take herbs such as black cohosh to manage menopausal symptoms (hot flushes and mood swings). Black cohosh appears to have a mechanism of action similar to that of estrogen in that it prevents hormones from reaching the brain to cause menopausal symptoms.36 The herb is safe and may represent an alternative option for women who refuse estrogen replacement therapy or in whom it is contraindicated.

REF: Kaiser Permanente Journal Winter 1999, Vol. 3 No.1 p.33 Philip J. Tuso, MD



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