title: Effects of herbal products on the metabolism and transport of anticancer agents.
abstract: BACKGROUND
  Cancer patients on chemotherapy treatment often seek herbal therapies and this may alter the clearance of anticancer drugs.
  
  
  METHODS
  Many anticancer drugs are metabolized by CYPs and are substrates of P-glycoprotein, breast cancer resistance protein and multi-drug resistance proteins. CYPs and drug transporters are subject to inhibition and/or induction by the herbal medicines used by cancer patients and the metabolism and pharmacokinetics of anticancer agents may be altered by herbal products. There are increased reports on the interaction of herbal medicines with anticancer agents. A clinical study in cancer patients reported that treatment of St John's wort at 900 mg/day orally for 18 days decreased the plasma levels of the active metabolite of irinotecan, SN-38, by 42%. In healthy subjects, treatment with St John's wort for 2 weeks significantly decreased the systemic exposure of imatinib by 32%. Induction and/or inhibition of CYPs and transporters is considered an important mechanism for these interactions.
  
  
  RESULTS
  Potential interactions of herbal medicines with anticancer agents have become a safety concern in cancer chemotherapy.
  
  
  CONCLUSIONS
  Further studies are warranted to investigate the efficacy and safety profiles of herbal medicines commonly used by cancer patients.
authors.affiliation: Xiaolan People's Hospital Affiliated to Nanfang Medical University, Department of Obstetrics and Gynecology, Zhongshan, Guangdong, China.
authors.forename: Shu-Ming
authors.initials: SM
authors.lastname: He
authors.forename: An-Kui
authors.initials: AK
authors.lastname: Yang
authors.forename: Xiao-Tian
authors.initials: XT
authors.lastname: Li
authors.forename: Yao-Min
authors.initials: YM
authors.lastname: Du
authors.forename: Shu-Feng
authors.initials: SF
authors.lastname: Zhou
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000493:pharmacokinetics* / Q000494:pharmacology; D001692:Biological Transport; D002986:Clinical Trials as Topic; D003577:Cytochrome P-450 Enzyme System / Q000187:drug effects / Q000378:metabolism; D041743:Herb-Drug Interactions; D006801:Humans; D020902:Hypericum / Q000737:chemistry; D009369:Neoplasms / Q000188:drug therapy*; D010936:Plant Extracts / Q000494:pharmacology
chemical_list: D000970:Antineoplastic Agents; D010936:Plant Extracts; D003577:Cytochrome P-450 Enzyme System