Mornitoring of the enantiomers of (?) -trans tramadol andits active metabolite in the serum of postoperative patients afterdifferent intravenous doses of (?)-trans tramadol hydrochloride injection / 中国临床药理学与治疗学

ABSTRACT

Aim To investigate the relationship between the clinical actions and the serum concentrations of the enantiomers of (?)-trans tramadol and its active metabolite. Methods 20 postoperative patients were divided into two groups and given multiple intravenous doses of (?)-trans tramadol hydrochloride injection, 400 mg?d-1 (group A) or 300 mg?d-1 (group B). The blood samples were taken at 38 h after the initial dose. The concentrations of the enantiomers of (?)-trans tramadol and its active metabolite, (?)-trans O-demethyltramadal were determined with high performance capillary electrophoresis(HPCE). Results The concentrations of the enantiomers of (?)-trans tramadol, the frequency and serious level of adverse reactions were higher in group A than in group B. The concentrations of the enantiomers of (?)-trans O-demethyltramadal, the analgesic effect were similar between group A and group B. Conclusion There is much closer relation between the analgesic effect and the concentration of (+)-O-demethyltramadal. The frequency and serious level of adverse reactions may be attributed to the higher concentrations of the enantiomers of (?)-trans tramadol, which are caused by the saturated metabolism.