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 […]

Combining Herbs And Antidepressants

Generally speaking, herbs should be combined cautiously with antidepressants and patients should be monitored carefully after starting combination therapy. There are few studies on whether herbs and antidepressant drugs work together well or might cause adverse effects. As cited above, St. John’s wort has been considered a potential threat in combination with antidepressant drugs, though very little evidence of difficulties has been documented. St. John’s wort should be used with caution with all types of antidepressant drugs but is not absolutely contraindicated in all cases. Table Antidepressant Drug-Herb Interactions reviews potential interactions of antidepressant drugs and herbs. Table Antidepressant Drug-Herb Interactions Herb Antidepressant Drug(s) Nature of Interaction Hypericum perforatum (St. John’s wort) SSRIs, MAOs, tricyclic antidepressants Unknown, potentially unsafe, do not combine without careful and close professional monitoring. Ginkgo biloba SSRIs, MAOs, tricyclic antidepressants Preliminary study shows reduction in sexual side effects. Pausinystalia yohimbe Fluvoxamine  (Luvox) Potentiated benefits in one clinical trial. Desipramine No negative 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: Isoflavones

Isoflavonoids This is a large group of related compounds with similar structures and biological properties in common, which are widely available as additives in dietary supplements as well as the herbs or foods that they were originally derived from. Isoflavones 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 isoflavones. The information in this monograph relates to the individual isoflavones, 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 isoflavones mentioned will interact in the same way. The levels of the isoflavone 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 Isoflavones are plant-derived polyphenolic compounds that are a distinct group of flavonoids. They can exert oestrogen-like effects, and therefore belong to the family of ‘phytoestrogens’. Most occur as simple isoflavones, but there are other derivatives Read more […]

Herb-Drug Interactions: Grapefruit

Citrus paradisi Macfad. (Rutaceae) Synonym(s) and related species Citrus paradisi Macfad. Grapefruit is a hybrid of the Pummelo or Pomelo (Citrus maxima (Burm.) Merr) with the sweet orange (Citrus sinensis (L.) Osbeck). Constituents Grapefruit contains furanocoumarins including bergamottin, 6′,7′-dihydroxybergamottin, bergapten, bergaptol, geranyl-coumarin and paradisin A, flavonoid glycosides such as naringin and flavonoid aglycones galangin, kaempferol, morin, naringenin, quercetin and others. The peel contains a volatile oil, mostly composed of limonene. Note that some grapefruit seed extracts have been found to contain preservatives such as benzethonium chloride, triclosan and methyl-p-hydroxybenzoate, which might be present because of the methods of production. Use and indications Grapefruit is used as a source of flavonoids (citrus bioflavonoids), which are widely used for their supposed antioxidant effects, and are covered under flavonoids. Grapefruit seed extracts are used for their antimicrobial properties, but there is some controversy that this might be due to preservative content rather than natural constituents. Grapefruit and grapefruit juice are commonly ingested as part of the diet, Read more […]

ANTIDEPRESSANTS

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 […]