It is increasingly common for patients to use western medications concurrently with Traditional Chinese
Medicine or other herbal medicines. Indeed, it is estimated that one-third of people in developed countries are using
alternative therapies including herbal medicines. Metabolism of drugs/herbs takes place to a large extent in the liver
and small intestine via various drug-metabolizing enzymes. Therefore, the concurrent use of western and herbal medicines
has potential for drug-herb interactions at these biological locations. There are several hepatic metabolic enzymes and
drug transporters that have been documented to be involved in the herb-drug interactions. These include the cytochrome
P450 (CYP450) enzymes that contribute to metabolism of various drugs, food constituents, and herbs, and the ATPbinding
cassette (ABC) transporters, particularly P-glycoprotein (P-gp), and solute carrier (SLC) transporters.
Pharmacogenetic variance in CYP450s and drug transporters in humans and animals may lead to pharmacokinetic and
pharmacodynamics changes of target substrates which could be drugs and/or herbal medicines. This paper presents a
synthesis of the emerging evidence on the role of pharmacogenetics in the mechanism of the salient herb-drug
interactions, and why the time has come to consider integrating this new strand of postgenomics knowledge to clinical and
public health practice.
Keywords: CYP 450, drug transporter, genetic polymorphism, herb-drug interaction, pharmacogenetics.
Rights & PermissionsPrintExport