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 […]

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: Coffee

Coffea L. species. (Rubiaceae) Synonym(s) and related species Arabian coffee is from Coffea arabica. Robusta coffee is from Coffea canephora (Pierre ex Froehner) also known as Coffea robusta (Linden ex De Wild.). Other species include Coffea liberica. Constituents The kernel of the dried coffee bean contains xanthine derivatives, the main one being caffeine (1 to 2%), with some theobromine and theophylline. It also contains polyphenolic acids such as chlorogenic acids and various diterpenes (e.g. kahweol, cafestrol). Use and indications Coffee has been used as a stimulant and diuretic. However, when roasted, coffee beans are most commonly used as a beverage. Pharmacokinetics The pharmacokinetics of caffeine are discussed under caffeine. Evidence suggests that chlorogenic acid is hydrolysed in the gastrointestinal tract to free caffeic acid, which is then conjugated to form the glucuronate or sulphate. Interactions overview Coffee contains significant amounts of caffeine, so the interactions of caffeine, are relevant to coffee, unless the product is specified as decaffeinated. By virtue of its caffeine content, coffee may also cause serious adverse effects if used with other drugs or herbs with similar Read more […]