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 […]


CALCIUM-CHANNEL BLOCKERS are agents that literally block or close any of the many types of calcium channels. However, in common usage the term is mainly used to describe a class of drugs finding increasing application in therapeutics (also called calcium antagonists or calcium-entry blockers) typified by the dihydropyridines (DHPs). In a more general usage of the term, there are many different classes of calcium-channel blockers, and many types of calcium channels. See CALCIUM-CHANNEL ACTIVATORS. First, in the cell membrane, the voltage-gated calcium channels are of at least six types — termed L, N, T, P, Q, R — that may be differentiated by electrophysiological, molecular cloning and pharmacological criteria. The L- and N-channels are high-voltage activated, voltage-dependent and undoubtedly of great importance in normal physiology; L mainly in smooth, cardiac and skeletal muscle (and some neurons), but N only in neurons. T-channels are important in repetitive activity in cardiac SA node of the heart, neurons and some endocrine cells. The remainder have been found more recently in neurons. These channels are products of different genes, but they all share great structural similarity — both with respect to Read more […]

Herb-Drug Interactions: Peppermint

Mentha piperita L. (Lamiaceae) Synonym(s) and related species Black mint (Mentha piperita Sole), White mint (Mentha piperita Sole). Note that Mentha x piperita L. is a hybrid between Mentha spicata L. and Mentha viridis L. Pharmacopoeias Concentrated Peppermint Emulsion (British Ph 2009); Gastro-resistant Peppermint Oil Capsules (British Ph 2009); Peppermint (US Ph 32); Peppermint Leaf (British Ph 2009, European Ph 2008); Peppermint Leaf Dry Extract (European Ph 2008); Peppermint Oil (British Ph 2009, European Ph 2008, US Ph 32); Peppermint Spirit (British Ph 2009, US Ph 32); Peppermint Water (The United States Ph 32). Constituents Essential oils, including menthol, menthone, menthyl acetate as the main components, and cineole, isomenthone, neomenthol, piperitone, pulegone and limonene. A maximum level of pulegone is permitted, since this is toxic, see pennyroyal. Peppermint also contains flavonoids such as rutin, menthoside, luteolin and phenolic acids, and lactones. Use and indications Peppermint leaf and distilled oil have carminative, antispasmodic, diaphoretic and antiseptic properties, and are mainly used to relieve symptoms of indigestion. Peppermint is commonly used as a flavouring ingredient Read more […]

Herb-Drug Interactions: Guggul

Commiphora wightii (Am.) Bhandari (Burseraceae) Synonym(s) and related species Mukul myrrh. Commiphora mukul Engl., Balsamodendrum wightii. Constituents The resinous sap, harvested from the tree bark by tapping, is extracted to produce guggul. Gugulipid is the purified standardised extract of crude gum guggul, and contains the active guggulsterone components Z-guggulsterone and E-guggulsterone, with cembrenoids, myrrhanone and myrrhanol derivatives. Use and indications Guggul is used mainly in Ayurvedic medicine and has been traditionally used to treat hypertension, osteoporosis, epilepsy, ulcers, cancer, obesity and rheumatoid arthritis. It is now often used for hyperlipidaemia, but clinical studies have found conflicting results for its lipid-lowering effects. Pharmacokinetics An in vitro study reported that gugulipid extract and purified guggulsterones may induce the expression of the cytochrome P450 isoenzyme CYP3A4. However, the clinical significance of this is unclear and further study is needed. Interactions overview In healthy subjects, the absorption of diltiazem and propranolol was modestly reduced by gugulipid. If the mechanism is confirmed, guggul might interact with a wide range of other Read more […]

Herb-Drug Interactions: Ginseng

Panax ginseng C.A.Mey (Araliaceae) Synonym(s) and related species Many species and varieties of ginseng are used. Panax ginseng C.A.Mey is also known as Asian ginseng. Chinese ginseng, Korean ginseng, Oriental ginseng, Renshen. Panax quinquefolius L. is also known as American ginseng. Other species used include: Panax notoginseng (Burkill) F.H.Chen ex C.Y.Wu & K.M.Feng known as Sanchi ginseng, Tienchi ginseng and Panax pseudo-ginseng Wall, also known as Himalayan ginseng. It is important to note that Siberian ginseng (Eleutherococcus senticosus Maxim.) is often used and marketed as a ginseng, but it is from an entirely different plant of the Araliaceae family and possesses constituents that are chemically different. It will be covered in this monograph with distinctions made throughout. Not to be confused with ashwagandha, which is Withania somnifera. This is sometimes referred to as Indian ginseng. Not to be confused with Brazilian ginseng, which is Pfaffia paniculata. Pharmacopoeias American Ginseng (US Ph 32); American Ginseng Capsules (US Ph 32); American Ginseng Tablets (US Ph 32); Asian ginseng (US Ph 32); Asian Ginseng Tablets (US Ph 32); Eleuthero (US Ph 32); Eleutherococcus (British 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 […]

Herb-Drug Interactions: Flavonoids

Bioflavonoids The flavonoids are a large complex group of related compounds, which are widely available in the form of dietary supplements, as well as in the herbs or foods that they are originally derived from. They are the subject of intensive investigations and new information is constantly being published. You may have come to this monograph via a herb that contains flavonoids. Note that the information in this general monograph relates to the individual flavonoids, and the reader is referred back to the herb (and vice versa) where appropriate. It is very difficult to confidently predict whether a herb that contains one of the flavonoids mentioned will interact in the same way. The levels of the flavonoid in the particular herb can vary a great deal between specimens, related species, extracts and brands, and it is important to take this into account when viewing the interactions described below. Types, sources and related compounds Flavonoids are a very large family of polyphenolic compounds synthesised by plants that are common and widely distributed. With the exception of the flavanols (e.g. catechins) and their polymers, the proanthocyanidins, they usually occur naturally bound to one or more sugar molecules Read more […]


ANTIARRHYTHMIC AGENTS (antidysrhythmic agents) are used to treat a number of heart conditions characterized by irregularities of heart beat. They have been classified under the Vaughan Williams Scheme, though not all clinically used agents neatly fit these classes. Class I (which has a number of subtypes) is mainly used to treat atrial and ventricular tachycardias, and contains a number of SODIUM-CHANNEL BLOCKERS, e.g. disopyramide, flecainide, lignocaine, procainamide and quinidine. Class II, which is valuable for stress-induced tachycardias, contains β-ADRENOCEPTOR ANTAGONISTS, e.g. metoprolol, propranolol. Class III, which is used for certain tachycardia syndromes, includes amiodarone (whose mechanism of action is not clear), POTASSIUM-CHANNEL BLOCKERS and the atypical β-blocker sotalol. Class IV is used for atrial tachyarrhythmias and contains certain CALCIUM-CHANNEL BLOCKERS, e.g. diltiazem and verapamil. In addition to drugs in these classes, others may be used for certain arrhythmias. Digoxin may be used for treatment of atrial fibrillation, adrenaline for asystolic cardiac arrest, atropine for sinus bradycardia, methacholine (rarely) for supraventricular tachycardia, magnesium salts for ventricular Read more […]


ANTIANGINAL AGENTS are used to relieve angina pectoris, an intense pain due to cardiac ischaemia, which is especially pronounced in exercise angina. The disease state often results from atheroma; a degeneration of the lining of the arteries of the heart due to build-up of fatty deposits. The objective is to relieve the heart of work, and to prevent spasm or to dilate coronary arteries. Unloading can be achieved by stopping exercise, preventing the speeding of the heart and by dilating the coronary arteries. Beta-blockers, by inhibiting the effect of adrenaline and noradrenaline on the heart, prevent the normal increase in heart rate, and are very effective in preventing exercise angina. Examples of beta-blockers used for this purpose include acebutolol, atenolol, metoprolol, nadolol, oxprenolol, pindolol, propranolol, sotalol and timolol. See β-ADRENOCEPTOR ANTAGONISTS. Many VASODILATORS act directly to relax vascular smooth muscle, so dilating blood vessels and thereby increasing blood flow (see SMOOTH MUSCLE RELAXANTS). For the acute treatment of anginal pain (and to a lesser extent in preventing angina attacks) the nitrates are widely used, e.g. glyceryl trinitrate, isosorbide dinitrate, isosorbide mononitrate Read more […]

Myrrh: Adverse Reactions. Significant Interactions. Pregnancy Use.

Toxicity A dose of 10 mg/kg/day was given to subjects in one study with no serious adverse effects. Adverse Reactions Restlessness, mild abdominal discomfort and gastrointestinal symptoms, such as diarrhea and nausea, have been reported, mainly with orally administered extracts. Allergic dermatitis has also been reported for topical usage. The standardised guggulsterone (guggulipid) preparations tend to be far better tolerated. Significant Interactions Interactions are theoretical and based on in vitro and in vivo data; therefore, clinical significance is unclear and remains to be confirmed. DIABETIC MEDICATION In vivo studies suggest myrrh may have hypoglycaemic effects and therefore would have additive effects with diabetic medications. Monitor for changes in serum glucose in patients taking these medications. LIPID-LOWERING MEDICATION Guggul may have cholesterol-lowering activity and therefore have additive effects with other lipid-lowering medications — observe patients taking this combination and monitor drug requirements. Beneficial interaction possible. ANTICOAGULANT AND ANTIPLATELET MEDICATION Guggul inhibited platelet aggregation in vitro and in a clinical study, therefore concurrent use may theoretically Read more […]