Investigation of interindividual variability in pharmacokinetics of and clinical responses to analgesics for cancer pain relief

2014 Fiscal Year Final Research Report

• Project/Area Number: 24590186
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Medical pharmacy
• Research Institution: Hamamatsu University School of Medicine
• Principal Investigator: KAWAKAMI Junichi 浜松医科大学, 医学部附属病院, 教授 (50272539)
• Co-Investigator(Kenkyū-buntansha): NAITO Takafumi 浜松医科大学, 医学部附属病院, 副薬剤部長 (80422749)
• Research Collaborator: YAGI Tatsuya 浜松医科大学, 医学部附属病院, 薬剤主任 (70719575) ; TANAKA Hironari 浜松医科大学, 医学部附属病院, 薬剤師
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: がん性疼痛 / 神経障害性疼痛 / ガバペンチン / トラマドール / オピオイド / 薬物動態 / 有害作用 / 遺伝子多型

Outline of Final Research Achievements

This study investigated the interindividual variability in the pharmacokinetics of gabapentin and tramadol in cancer pain patients. Concomitant magnesium oxide decreased the gabapentin exposure through the reduction of intestinal absorption extent and rate in healthy subjects. Patients with neuropathic pain also had the lower plasma disposition of gabapentin with concomitant magnesium oxide administration. In the patients with neuropathic pain, the genetic polymorphisms of organic cation transporters, OCTN1 and OCTN2, did not affect the pharmacokinetics of gabapentin.
A simultaneous and isocratic LC-MS/MS method for the determination of tramadol and O-, N-, N,O-desmethyl metabolites in the plasma of cancer patients has been established. This method possesses acceptable degrees of precision and accuracy in accordance with US FDA guidelines. Cancer patients had the interindividual variations in plasma concentrations of tramadol and its metabolites.

Free Research Field

医歯薬学