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 […]


GLUCOCORTICOIDS are members of the corticosteroid family, with actions similar to the steroid hormones secreted by the adrenal cortex. There are two main types of corticosteroids: glucocorticoids and MINERALOCORTICOIDS. Glucocorticoids that are important physiologically include hydrocortisone (cortisol), corticosterone and cortisone. These are essential for utilization of carbohydrate, fat and protein in the body, and in the normal response to stress. Naturally occurring and synthetic glucocorticoids have a powerful antiinflammatory effect. In contrast, the mineralocorticoids (e.g. aldosterone) are necessary for the regulation of the salt and water balance of the body. Corticosteroids can be used in hormone replacement therapy. For instance, the glucocorticoid hydrocortisone and the mineralocorticoid fludrocortisone can be given to patients for replacement therapy where there is a deficiency, or in Addison’s disease, or following adrenalectomy or hypopituitarism. The glucocorticoids are potent antiinflammatory and antiallergic agents, frequently used to treat inflammatory and/or allergic reactions of the skin, airways and elsewhere. Absorption of a high dose of corticosteroid over a period of time may also cause undesirable Read more […]

Herb-Drug Interactions: Liquorice

Qycyrrhiza glabra L. (Fabaceae) Synonym(s) and related species Licorice. Spanish and Italian liquorice is Glycyrrhiza glabra var typica Reg. et Herd. Persian or Turkish liquorice is Glycyrrhiza glabra L var violacea Boiss. Russian liquorice is Glycyrrhiza glabra L var glanduli-fera. Chinese liquorice is the closely related Glycyrrhiza uralensis Fisch., also known as Gancao. Pharmacopoeias Licorice (US Ph 32); Liquorice (British Ph 2009); Liquorice Dry Extract for Flavouring Purposes (British Ph 2009); Liquorice Liquid Extract (British Ph 2009); Liquorice Root (European Ph 2008); Liquorice Root for use in THM (British Ph 2009); Powdered Licorice (US Ph 32); Powdered Licorice Extract (US Ph 32); Processed Liquorice Root for use in THMP (British Ph 2009); Standardised Liquorice Ethanolic Liquid Extract (British Ph 2009, European Ph, 6th ed., 2008 and Supplements 6.1, 6.2, 6.3 and 6.4). Constituents Liquorice has a great number of active compounds of different classes that act in different ways. The most important constituents are usually considered to be the oleanane-type triterpenes, mainly glycyrrhizin (glycyrrhizic or glycyrrhizinic acid), to which it is usually standardised, and its aglycone glycyrrhetinic Read more […]

Herb-Drug Interactions: Garlic

Allium sativum L. (Alliaceae) Synonym(s) and related species Ajo, Allium. Pharmacopoeias Garlic (US Ph 32); Garlic Delayed Release Tablets (US Ph 32); Garlic Fluid Extract (US Ph 32); Garlic for Homeopathic Preparations (British Ph 2009, European Ph 2008); Garlic Powder (European Ph, 6th ed., 2008 and Supplements 6.1, 6.2, 6.3 and 6.4, British Pharmacopoeia 2009); Powdered Garlic (US Ph 32); Powdered Garlic Extract (The United States Ph 32). Constituents Garlic products are produced from the bulbs (cloves) of garlic and are usually standardised according to the content of the sulphur-containing compounds, alliin, allicin (produced by the action of the enzyme alliinase on alliin) and/or γ-glutamyl-(S)-allyl-L-cysteine. Other sulphur compounds such as allylmethyltrisulfide. allylpropyldisulfide, diallyldisulfide, diallyltrisulfide, ajoene and vinyldithiines, and mercaptan are also present. Garlic also contains various glycosides, monoterpenoids, enzymes, vitamins, minerals and flavonoids based on kaempferol and quercetin. Use and indications Garlic has been used to treat respiratory infections (such as colds, flu, chronic bronchitis, and nasal and throat catarrh) and cardiovascular disorders. It is believed Read more […]

Gymnema Sylvestre: Background. Actions

Historical Note Gymnema has been called the sugar destroyer because the leaf suppresses the ability to taste sweet on the tongue. It has been used to treat diabetes, as well as to aid metabolic control when combined with other herbal medicines. Common Name Gymnema Other Names Asclepias geminate, gur-mar (sugar destroyer), gemnema melicida, gokhru, gulrmaro, gurmar, gurmara, gurmarbooti, kar-e-khask, kharak, merasingi, meshasringi, masabedda, Periploca sylvestris, sirukurinjan Botanical Name / Family Gymnema sylvestre (family Asclepiadaceae) Plant Part Used Leaf Chemical Components Gymnema contains gymnemasaponins, gymnemasides, gymnemic acids and gypenosides, as well as a range of nutrients including ascorbic acid, beta-carotene, chromium, iron, magnesium and potassium. The main active chemical components appear to be the gymnemic acids, gymnemasaponins and the polypep-tidegurmarin. Main Actions SWEET TASTE SUPPRESSION The constituent, gymnemic acid, inhibits the ability to taste sweetness in animal models and humans. In humans, the administration of 5 mmol/L gurmarin to the tongue raised the threshold ability to taste sucrose from 0.01 mol/L to 1 mol/L for several hours. It is suggested that gurmarin Read more […]


ANTIEMETICS are used to prevent vomiting. They are thus related to antinauseant drugs which are used to reduce or prevent the feeling of nausea that very often precedes the physical process of vomiting (emesis). Commonly, the terms are used synonymously, though it is usually an antinauseant action that is being sought. The type of antinauseant drugs used, and the likelihood of success, depends on the mechanism and origin of the nauseous sensation, and there are a number of ways it can be triggered. Motion sickness (travel sickness) can often be prevented by taking antinauseant drugs before travelling, e.g. the antihistamines meclozine and dimenhydrinate, and the anticholinergic hyoscine. Probably all these drugs act as central MUSCARINIC CHOLINOCEPTOR ANTAGONISTS. Similar drugs may be used to treat nausea and some other symptoms of labyrinthine disease (where the vestibular balance mechanisms of the inner ear are disturbed, e.g. in Meniere’s disease), though other antinauseant drugs may also be necessary, e.g. cinnarizine or phenothiazine derivatives such as chlorpromazine and prochlorperazine. Steroids, such as dexamethasone and methylprednisolone, are effective antiemetics that work by an undefined mechanism. In view Read more […]