Herb-drug interactions: review and assessment of report reliability.

AIMS: The aim of this systematic review was to assess the published clinical evidence on interactions between herbal and conventional drugs. METHODS: Four electronic databases were searched for case reports, case series or clinical trials of such interactions. The data were extracted and validated using a scoring system for interaction probability. RESULTS: One hundred and eight cases of suspected interactions were found. 68.5% were classified as 'unable to be evaluated', 13% as 'well-documented' and 18.5% as 'possible' interactions. Warfarin was the most common drug (18 cases) and St John's wort the most common herb (54 cases) involved. CONCLUSION: Herb-drug interactions undoubtedly do occur and may put individuals at risk. However our present knowledge is incomplete and more research is urgently needed.

Red clover (Trifolium pratense) for menopausal women: current state of knowledge.

OBJECTIVE: Red clover (Trifolium pratense) extracts are becoming increasingly popular, primarily for the treatment of menopausal symptoms. Although promoted as a phytoestrogen source similar to soybeans, red clover is a medicinal herb, not a food, and traditionally has not been used long-term. We sought to review the scientific literature for this newer use. DESIGN: Medline was searched for controlled trials of red clover (Trifolium pratense), and other sources were searched for other studies and abstracts. RESULTS: Two double-blind placebo-controlled trials found no beneficial effects of red clover extracts on hot flashes or other menopausal symptoms. Three of four trials examining the effect of red clover on lipids found no benefit; the fourth trial contains too little data to interpret. One study examining the effect of red clover on arterial compliance found a significant beneficial effect on arterial compliance. CONCLUSION: Red clover extracts have as yet no clear demonstrable benefit for menopausal symptoms. Potential estrogenic effects on breast and endometrium have not been adequately assessed. The presence of coumarins in some clover species makes it imperative to include tests of clotting factors in future trials.

Complementary and alternative medicine in the management of pain, dyspnea, and nausea and vomiting near the end of life. A systematic review.

To review the evidence for efficacy of complementary and alternative medicine (CAM) modalities in treating pain, dyspnea, and nausea and vomiting in patients near the end of life, original articles were evaluated following a search through MEDLINE, CancerLIT, AIDSLINE, PsycLIT, CINAHL, and Social Work Abstracts databases. Search terms included alternative medicine, palliative care, pain, dyspnea, and nausea. Two independent reviewers extracted data, including study design, subjects, sample size, age, response rate, CAM modality, and outcomes. The efficacy of a CAM modality was evaluated in 21 studies of symptomatic adult patients with incurable conditions. Of these, only 12 were directly accessed via literature searching. Eleven were randomized controlled trials, two were non-randomized controlled trials, and eight were case series. Acupuncture, transcutaneous electrical nerve stimulation, supportive group therapy, self-hypnosis, and massage therapy may provide pain relief in cancer pain or in dying patients. Relaxation/imagery can improve oral mucositis pain. Patients with severe chronic obstructive pulmonary disease may benefit from the use of acupuncture, acupressure, and muscle relaxation with breathing retraining to relieve dyspnea. Because of publication bias, trials on CAM modalities may not be found on routine literature searches. Despite the paucity of controlled trials, there are data to support the use of some CAM modalities in terminally ill patients. This review generated evidence-based recommendations and identified areas for future research.

Herb-drug interactions.

Concurrent use of herbs may mimic, magnify, or oppose the effect of drugs. Plausible cases of herb-drug interactions include: bleeding when warfarin is combined with ginkgo (Ginkgo biloba), garlic (Allium sativum), dong quai (Angelica sinensis), or danshen (Salvia miltiorrhiza); mild serotonin syndrome in patients who mix St John's wort (Hypericum perforatum) with serotonin-reuptake inhibitors; decreased bioavailability of digoxin, theophylline, cyclosporin, and phenprocoumon when these drugs are combined with St John's wort; induction of mania in depressed patients who mix antidepressants and Panax ginseng; exacerbation of extrapyramidal effects with neuroleptic drugs and betel nut (Areca catechu); increased risk of hypertension when tricyclic antidepressants are combined with yohimbine (Pausinystalia yohimbe); potentiation of oral and topical corticosteroids by liquorice (Glycyrrhiza glabra); decreased blood concentrations of prednisolone when taken with the Chinese herbal product xaio chai hu tang (sho-salko-to); and decreased concentrations of phenytoin when combined with the Ayurvedic syrup shankhapushpi. Anthranoid-containing plants (including senna [Cassia senna] and cascara [Rhamnus purshiana]) and soluble fibres (including guar gum and psyllium) can decrease the absorption of drugs. Many reports of herb-drug interactions are sketchy and lack laboratory analysis of suspect preparations. Health-care practitioners should caution patients against mixing herbs and pharmaceutical drugs.

Herbs and dietary supplements in the prevention and treatment of cardiovascular disease.

Herbs and dietary supplements can have significant physiological effects. Garlic (Allium sativum) has shown beneficial lipid effects in a majority of trials; dried garlic preparations are superior to oil preparations. There is preliminary evidence that indicates that hawthorn (Crataegus species) may provide benefits in congestive heart failure. Coenzyme Q also may be of benefit in congestive heart failure. Although observational studies indicate a protective effect of dietary or supplemental vitamin E, controlled trails have not shown a beneficial effect on angina and have been mixed on whether supplementation decreases major cardiac events. Although several observational studies have noted that fish intake protects against cardiovascular disease, prospective studies are less impressive. Fish oil supplementation may have a mild beneficial effect on hypertension, but there is no effect on total cholesterol levels. Trials are inconsistent on whether fish oil reduces restenosis rates following coronary angioplasty. Carnitine appears to have beneficial effects on congestive heart failure and angina; there is also preliminary evidence that arginine may benefit patients with congestive heart failure or angina. Herbs and supplements have been associated with adverse effects and interactions; for example, garlic inhibits platelet aggregation and can cause significant anticoagulation, and the Chinese herb danshen (Salvia miltiorrhiza) appears to potentiate warfarin. Several herbs and supplements hold promise as adjuncts in the prevention and treatment of cardiovascular disease. There is a need for definitive research on the potential risks and benefits of these compounds, including appropriate dosages and formulations, and delineation of adverse events and interactions. (c)2000 by CHF, Inc.

Dietary supplements and natural products as psychotherapeutic agents.

Alternative therapies are widely used by consumers. A number of herbs and dietary supplements have demonstrable effects on mood, memory, and insomnia. There is a significant amount of evidence supporting the use of Hypericum perforatum (St. John's wort) for depression and Ginkgo biloba for dementia. Results of randomized, controlled trials also support the use of kava for anxiety and valerian for insomnia. Although evidence for the use of vitamins and amino acids as sole agents for psychiatric symptoms is not strong, there is intriguing preliminary evidence for the use of folate, tryptophan, and phenylalanine as adjuncts to enhance the effectiveness of conventional antidepressants. S-adenosylmethionine seems to have antidepressant effects, and omega-3 polyunsaturated fatty acids, particularly docosahexaenoic acid, may have mood-stabilizing effects. More research should be conducted on these and other natural products for the prevention and treatment of various psychiatric disorders.

Is St. John's wort (Hypericum perforatum) an effective antidepressant?

SJW is a remarkably safe antidepressant with an apparently unique mode of action. Although it has demonstrated efficacy in mild and moderate depression when compared with placebo or tricyclic antidepressants, several research areas beg to be explored. Its effects should be compared with serotonin reuptake inhibitors. Studies in severely depressed patients are lacking, as are studies on its utility as a therapeutic adjunct to standard antidepressants.

Clinical trials of herbs.

Consumers, clinicians, and corporations are taking an interest in botanical medicine. Although large gaps remain in research, many clinical trials of herbs exist. This article reviews these trials.