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 […]

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 […]

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 […]


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 […]

St John’s wort: Clinical Use

Up until recently, most trials conducted with St John’s wort used a 0.3% hypericin water and alcohol extract known as LI 150. Subsequently, studies using different preparations, such as WS 5573 (standardised to hyperforin) or ZE 117 (a low concentration hyperforin preparation), have been tested. DEPRESSION AND ANXIETY Clinical note — The Hamilton Depression Scale The Hamilton Depression Scale is an observer-rated scale that focuses mainly on somatic symptoms of depression. Although the original version included 21 items, a similar version using 17 items is more commonly used in clinical trials. Most studies using the Hamilton Depression Scale report the number of ‘treatment responders’ (patients achieving a score less than 10 and/or less than 50% of the baseline score). Mild to moderate depression St John’s wort has shown efficacy as a successful treatment for mild to moderate depression in numerous double-blind placebo-controlled trials, confirmed by several meta-analyses. The most recent Cochrane review released in 2005 analysed data from 37 double-blind, randomised studies (n = 4925) that used monopreparations of St John’s wort over a treatment period of at least 4 weeks. It concluded that hypericum Read more […]