Figure 5.

Correlation between the mean (+)/(−)‐enantiomer ratios of tramadol, O‐desmethyltramadol, N‐desmethyltramadol and N,O‐didesmethyltramadol, and time in CYP2D6 poor (PMs), intermediate (IMs) and extensive metabolizers (EMs), respectively. The healthy volunteers were administered an oral, single dose of either 50 or 100 mg tramadol. One of the two PMs never achieved concentrations of (+)‐O‐desmethyltramadol or (+)‐N,O‐didesmethyltramadol above the limit of quantification, and subsequently enantiomer ratios could not be calculated