Netilmicin pharmacokinetics in Hong Kong Chinese cancer patients

Objectives To study the pharmacokinetics of netilmicin in Chinese haematolo gy-oncology patients and to determine the pharmacokinetic differences,, if any, between this patient subpopulation of Chinese and Caucasians. Methods A prospective study was carried out in the adult oncology unit of a major hospital in Hong Kong. During a 6 week period in 1997, all patients commencing on netilmicin therapy were monitored; the patients' demographics , clinical status, netilmicin dose and regimen, and drug administration/blo od sampling time were collected. Pharmacokinetic parameters were generated using the USC(star)PACK package based on specifics of the patients themselv es and Caucasians matched for the same patients' parameters using the Bayes ian alogrithms. Results A total of 22 patients were enrolled into the study. Twenty-nine se ts of levels were drawn, but only 25 sets from 18 patients (86%) were inter pretable. The predicted peak (7.47 +/- 1.46 mu g ml(-1)) and trough levels (1.39 +/- 0.96 mu gml(-1)) generated by USC(star)PACK were found to be sign ificantly higher than the levels observed (6.01 +/- 1.14 mu g ml(-1) and 0. 93 +/- 0.71 mu g ml(-1), respectively). Netilmicin clearance, volume of dis tribution and rate of elimination were all significantly higher in this Chi nese subpopulation than those predicted for matched Caucasians. Conclusion Alterations in the netilmicin pharmacokinetics observed in our s tudy population might be related to the disease state and/or ethics of the study patient population. Direct application of Caucasian based population pharmacokinetic parameters to this subgroup of Chinese patients may not be appropriate and may result in underdose.