Prolonged presence of metabolite in urine after compulsive cocaine use.

The authors studied the pattern of benzoylecgonine excretion in 35 male veterans who had recently used large amounts of cocaine. Following admission to a drug-free environment, the veterans completed a short structured interview and gave daily urine samples for benzoylecgonine analysis. Eleven (31.4%) patients excreted benzoylecgonine at levels of 300 ng/mL or above for 120 hours or longer after admission. Eight (22.9%) patients whose enzyme-multiplied immunoassay test results were negative subsequently tested positive. These findings corroborate recent case reports of prolonged presence of benzoylecgonine in the urine and have important implications for drug treatment programs.