Article date: December 1989
By: QY Yue, JO Svensson, C Alm, F Sjoqvist, J Sawe, in Volume 28, Issue 6, pages 629-637
1. The 8 h urinary excretion of codeine and seven of its metabolites was compared in 149 healthy Swedish Caucasians and 133 healthy Chinese following a single oral dose of 25 mg codeine phosphate. 2. The total 8 h urinary recovery of drug‐related material was 74 +/‐ 24% in the Caucasians and 60 +/‐ 14% in the Chinese (P less than 0.001). The excretion of unchanged codeine was significantly higher in the Chinese (7.2%) compared with the Caucasians (4.3%, P less than 0.001). 3. The Caucasians excreted significantly greater proportions of codeine‐6‐ glucuronide (C6G) (62%) than the Chinese (44%) (P less than 0.001). The frequency distribution of the log metabolic ratio (MR) for glucuronidation (codeine/C6G) was shifted towards higher values in the Chinese population. Males in both groups and Chinese smokers had significantly lower glucuronidation MRs than females and non‐smokers in the respective populations (P less than 0.001). 4. The frequency distribution of the MR for O‐demethylation (codeine/morphine (M) + M‐3 and M‐6‐glucuronide (M3G and M6G) + normorphine (NM) was highly skewed in the Caucasians, suggestive of a bimodal distribution. There was a 160‐fold interindividual variation in this MR. A unimodal distribution of the log O‐demethylation MR was observed in Chinese. The Caucasians excreted less M and more M6G than did the Chinese (P less than 0.001). 5. Significantly more norcodeine (NC) and less NC‐glucuronide (NCG) were excreted in the Chinese compared with the Caucasians (P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
DOI: 10.1111/j.1365-2125.1989.tb03555.x
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