Asteraceae: Drug Interactions, Contraindications, And Precautions

Patient survey data from Canada, the U.S., and Australia show that one in five patients use prescription drugs concurrently with CAM. The inherent polypharmaceutical nature of complementary and alternative medicine increases the risk of adverse events if these complementary and alternative medicine either have pharmacological activity or interfere with drug metabolism. Since confirmed interactions are sporadic and based largely on case reports, advice to avoid certain drug-CAM combinations is based on known pharmacological and in vitro properties. Known Hypersensitivity to Asteraceae Cross-reactive sesquiterpene lactones are present in many, if not all, Asteraceae. Patients with known CAD from one plant may develop similar type IV reactions following contact with others. Affected patients are often advised to avoid contact with all Asteraceae, yet this advice is based on limited knowledge of cross-reactivity between relatively few members of this large family. Some authorities recommend avoiding Asteraceae-derived complementary and alternative medicine if, for example, the patient is known to have IgE-mediated inhalant allergy to ragweed. While a reasonable approach, this ignores a number of important facts: (1) Read more […]

St. John’s Wort (Hypericum perforatum)

St. John’s Wort: Medical Uses St. John’s wort is taken orally for mild to moderate depression, not for severe depression or bipolar disorder. It can be used externally for tennis elbow, sprains, and strains. Historical Uses St. John’s wort was used by the ancient Greeks for sciatica and nervous disorders. It has also been used as a popular folk remedy for neuralgias, sciatica, burns or bruises involving nerve damage, sprains, emotional disorders, wounds, and tennis elbow. Growth This plant grows in fields and on roadsides throughout the United States. It reaches about 1 to 3 feet in height, and its yellow flowers bloom from June to September. Parts Used • Aerial (above-ground) parts Major Chemical Compounds • Hypericin • Hyperforin • Flavonoids St. John’s Wort: Clinical Uses St. John’s wort is given orally for mild to moderate depression, not for severe depression or bipolar disorder. It can be used externally for tennis elbow, sprains, and strains. It is approved by the German Commission E to be used “internally for depressive moods, anxiety, externally for acute and contused injuries, myalgia, and first-degree burns”. St. John’s wort is at least as safe as, and possibly safer than, fluoxetine Read more […]

Hypericum perforatum

St John’s wort (Hypericum perforatum) is a native flowering plant of Europe and Asia which produces attractive yellow flowers. According to Kiple and Ornelas (2000) its lemon-scented leaves have been used for thousands of years as human food and have also been used to make a form of tea. Extracts of the flowers and leaves of this plant are now widely taken in the belief that they are mood enhancing and have beneficial effects in the treatment of clinical depression. In Germany hypericum extracts are widely prescribed by physicians for the treatment of clinical depression and it is the best selling antidepressant there. What is depression? Clinical depression is a common, painful and disabling condition which is more severe than the normal downward fluctuations in mood that we all regularly experience. The American Psychiatric Association lists the following symptoms for depression: • Depressed mood • Loss of interest in and lack of pleasure derived from activities that the patient usually finds pleasurable • Disturbed sleep patterns • Abnormal activity patterns, either agitation or being uncharacteristically inactive • Loss of drive and energy, loss of sex drive and reduced appetite To Read more […]

Cerebrovascular Insufficiency And Depression

Atherosclerosis of the vasculature feeding the brain can lead to a condition known as cerebrovascular insufficiency. This chronic low-grade ischemia can impair memory or otherwise mimic dementia. It can also produce a syndrome resembling depression. This syndrome is surprisingly little discussed in the United States but is much more widely recognized in Europe. The treatment is obviously the same as for atherosclerosis anywhere in the body — elimination of the underlying dietary and lifestyle causes (especially sedentariness) and addition of supportive nutrients and practices (like meditation). Ginkgo biloba (ginkgo) leaf extracts have been very rigorously shown to help alleviate cerebrovascular insufficiency symptoms. This is almost certainly due to ginkgo’s ability to reduce the underlying atherosclerosis and improve neuron function despite ischemia. It also seems to stimulate blood flow to the brain, perhaps by acting on blood vessels. The usual dose of ginkgo standardized extract is 80-160 mg two or three times per day. It should be used attentively in patients taking anticoagulants as the combination occasionally but rarely may have a synergistic effect and cause bleeding. Gingko has also been shown to Read more […]

Overlooked Herbs

A variety of gentle plants are continually overlooked by both pharmacological medicine and clinical practitioners. This happens because it is easy to fall into the trap of looking for rapid-acting, potent plants with a specificity for a particular disease state. It is all too easy to overlook plants that act slowly and nonspecifically but in the end help address the root cause of the problem. Throughout history herbal practitioners have emphasized the importance of these “tonics” (sometimes referred to as neurotrophorestoratives) to help support the patient’s own healing process. Herbs that support the integrity and function of the nervous system are almost universally indicated for people with depression. Moreover, nervine tonics are usually called for because depression often exists as “a comorbid condition,” very often with anxiety or other mood disorders. Avena saliva (oats) seeds (picked during the so-called milky stage) are one of the most highly reputed and gentle nerve tonics among the Eclectic physicians as well as European herbalists. Oat seed also has a reputation, however poorly substantiated, for relieving depression and thus cravings in people attempting to break their addiction to nicotine. It might Read more […]

Herb-Drug Interactions: Cannabis

Cannabis sativa L. (Cannabaceae) Synonym(s) and related species Bhang, Dagga, Ganja, Hashish, Indian hemp, Marihuana, Marijuana. Cannabis indica Lam. Constituents Cannabis herb contains a wide range of cannabinoids, which are the major active compounds. The main psychoactive constituent is delta9-tetrahydrocannabinol (THC; dronabinol), and it is the cause of many of the pharmacological effects elicited by the consumption of cannabis. However, other cannabinoids, which do not possess psychoactive properties, such as cannabidiol, cannabinol (a decomposition product of delta9-tetrahydrocannabinol), cannabigerol and cannabichromene, are increasingly being investigated for their pharmacological and therapeutic properties. Cannabinoids are often found in the plant as their acid metabolites, e.g. ll-nor-9-carboxy-delta9-tetrahydrocannabinol, cannabidiol acid and others, especially if the plant has been grown in a cooler climate. These decarboxylate to the parent cannabinoid at high temperatures, such as during smoking. Most medicinal cannabis products have been heat treated to ensure that the cannabinoids are present only in the non-acid form. Use and indications Cannabis has no current established use in herbal Read more […]

Herb-Drug Interactions: St John’s wort

Hypericum perforatum L. (Clusiaceae) Synonym(s) and related species Hypericum, Millepertuis. Hypericum noeanum Boiss., Hypericum veronense Schrank. Pharmacopoeias St John’s Wort (British Ph 2009, European Ph 2008, US Ph 32); St John’s Wort Dry Extract, Quantified (British Ph 2009, European Ph, 6th ed., 2008 and Supplements 6.1, 6.2, 6.3 and 6.4). Constituents The main groups of active constituents of St John’s wort are thought to be the anthraquinones, including hypericin, isohypericin, pseudohypericin, protohypericin, protopseudohypericin and cyclopseudohypericin, and the prenylated phloroglucinols, including hyperforin and adhyperforin. Flavonoids, which include kaempferol, quercetin, luteolin, hyperoside, isoquercitrin, quercitrin and rutin; biflavonoids, which include biapigenin and amentoflavone, and catechins are also present. Other polyphenolic constituents include caffeic and chlorogenic acids, and a volatile oil containing methyl-2-octane. Most St John’s wort products are standardised at least for their hypericin content (British Pharmacopoeia 2009), even though hyperforin is known to be a more relevant therapeutic constituent, and some preparations are now standardised for both (The United Read more […]

Herb-Drug Interactions: Melatonin

N-(2-(5-Methoxyindol-3-yl)ethyl)acetamide Types, sources and related compounds N- Acetyl-5-methoxytryptamine. Use and indications Melatonin is a hormone that is produced in the pineal gland of the brain and influences the circadian rhythm. Supplements are therefore principally used for treating sleep disturbances and disorders such as jet lag, insomnia, sleep walking, and shift-work sleep disorder. It is also believed to have anticancer and antihypertensive properties, and has been used to treat cluster headaches. Melatonin has also been detected in a large number of plant species, including those used as foods. Concentrations detected have been very variable, the reasons for which are currently uncertain. In addition, the importance of dietary melatonin is unclear. Pharmacokinetics When an oral melatonin supplement 3mg was given to 17 healthy subjects the AUC and maximum serum levels of melatonin were about 18-fold and 100-fold greater, respectively, than overnight endogenous melatonin secretion, although there was a wide variation between individuals.The oral bioavailability was approximately 15% after oral doses of 2 or 4mg, possibly due to significant first-pass metabolism. The half-life has been found Read more […]

Herb-Drug Interactions: Ginkgo

Ginkgo biloba L. (Ginkgoaceae) Synonym(s) and related species Fossil tree, Kew tree, Maidenhair tree. Salisburia adiantifolia Sm., Salisburia biloba Hoffmanns. Pharmacopoeias Ginkgo (US Ph 32); Ginkgo capsules (US Ph 32); Ginkgo dry extract, refined and quantified (British Ph 2009, European Ph 2008); Ginkgo leaf (British Ph 2009, European Ph, 6th ed., 2008 and Supplements 6.1, 6.2, 6.3 and 6.4); Ginkgo tablets (US Ph 32); Powdered ginkgo extract (The United States Ph 32). Constituents Ginkgo leaves contain numerous flavonoids including the biflavone glycosides such as ginkgetin, isoginkgetin, bilobetin, sciadopitysin, and also some quercetin and kaempferol derivatives. Terpene lactones are the other major component, and these include ginkgolides A, B and C, and bilobalide, Ginkgo extracts may be standardised to contain between 22 and 27% flavonoids (flavone glycosides) and between 5 and 12% terpene lactones, both on the dried basis. The leaves contain only minor amounts of ginkgolic acids, and some pharmacopoeias specify a limit for these. The seeds contain ginkgotoxin (4-O-methylpyridoxine) and ginkgolic acids. Use and indications The leaves of ginkgo are the part usually used. Ginkgo is often used Read more […]


ANTIDEPRESSANTS are used to relieve the symptoms of depressive illness, an affective disorder. There are three main groups of drugs used for the purpose. All interfere with the function of monoamine neurotransmitters, and the considerable delay before antidepressants become effective is taken as evidence of a down-regulation of noradrenergic or serotonergic systems (rather than the opposite, as advanced in Schildkraut’s original amine theory of depression). Tricyclic antidepressants are the oldest group (named after the chemical structure of the original members) .e.g. imipramine. They act principally as CNS monoamine (re-) UPTAKE INHIBITORS. Although far from ideal, this is still the most-used antidepressant group. Chemically, they have gone through transformations from the dibenzazepines (e.g. imipramine, desipramine), to dibenzcycloheptenes (e.g. amitriptyline, nortryptyline), dibenzoxepines (e.g. doxepin) and some recent members are not strictly tricyclics. They are effective in alleviating a number of depressive symptoms, though they have troublesome anticholinergic and other side-effects. Most drugs of this class also have sedative properties, which is more pronounced in some, especially amitriptyline, which Read more […]