Cocaine and its major metabolites in plasma and urine samples from patients in an urban emergency medicine setting

In this retrospective study, we examined the levels of cocaine and its major metabolites in plasma and urine from 29 randomly selected emergency department patients (19 males and 10 females, aged 19 to 55) whose urine screened positive for benzoylecgonine using fluorescence polarization immunoassay. Levels of cocaine along with benzoylecgonine, ecgonine methyl ester, and norcocaine were quantitated in EDTA plasma and urine from each patient using gas chromatography-mass spectrometry with selected ion monitoring. Admission diagnosis and history were also obtained for each patient. In plasma, the levels were 16-130 ng/mL for cocaine (n = 3), 27-96 ng/mL for ecgonine methyl ester (n = 9), and 18-1390 ng/mL for benzoylecgonine (n = 22). Norcocaine was not detected in any of the plasma samples. In urine, the concentration ranges were 4-40,130 ng/mL for cocaine (n = 23), 36-660,500 ng/mL for ecgonine methyl ester (n = 27), and 9-2520 ng/mL for norcocaine (n = 9). All urine samples were positive for benzoylecgonine (106-3,361,000 ng/mL), and benzoylecgonine was the only metabolite present in two urine samples (at concentrations of 407 and 435 ng/mL). Two patients had plasma and urine samples positive for all analytes (except norcocaine in plasma). The patient with the highest urinary concentrations of cocaine (40,130 ng/mL), ecgonine methyl ester (660,500 ng/mL), benzoylecgonine (3,361,000 ng/mL), and norcocaine (2520 ng/mL) had a small quantity of benzoylecgonine (465 ng/mL) in plasma. No correlation was noted with patient history, admitting diagnosis or symptomatology, or plasma/urine levels of cocaine or any of its metabolites.