Occurrence of cocaine in urine of substance-abuse treatment patients.
As part of ongoing research efforts to improve methods of monitoring drug use in treatment patients, the presence of cocaine in urine specimens was evaluated as a possible marker for recent illicit cocaine use. A total of 2327 urine specimens collected during a 17-week clinical trial of a cocaine-abuse treatment study were tested. Cocaine was measured by gas chromatography-mass spectrometry, and benzoylecgonine (BZE) equivalents were determined by fluorescence polarization immunoassay (FPIA). More than one-third of the specimens were positive (> 25 ng/mL) for cocaine (36.8%), and nearly two-thirds were positive (> 300 ng/mL) for cocaine metabolite by FPIA (62.7%). Median concentrations of cocaine and BZE equivalents were 235 and 14,900 ng/mL, respectively, and maximum concentrations were 112,025 and 1,101,190 ng/mL in cocaine- and BZE-positive specimens, respectively. There were 52 specimens that contained cocaine in equal or higher concentrations than BZE equivalents. No significant differences in cocaine or BZE concentrations between Caucasian and African-American or between male and female patients were found. Cocaine was present less frequently and at lower concentrations than BZE but more frequently than expected based on an average half-life of approximately 1 h, which suggests that cocaine may exhibit a longer terminal half-life and/or that accumulation of cocaine can occur in chronic, heavy users.
Preston
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National Institute on Drug Abuse, Intramural Research Program, Baltimore, Maryland 21224, USA.
Goldberger
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BA
Cone
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EJ
D000293:Adolescent; D000328:Adult; D001741:Black or African American; D000368:Aged; D003042:Cocaine / Q000652:urine*; D005260:Female; D016231:Fluorescence Polarization Immunoassay; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D008297:Male; D008875:Middle Aged; D012737:Sex Factors; D015813:Substance Abuse Detection; D016320:Substance Abuse Treatment Centers; D019966:Substance-Related Disorders / Q000652:urine*; D044465:White People
D003042:Cocaine