Cocaethylene levels in patients who test positive for cocaine

Study objective: To determine the presence of cocaethylene, an active metabolite of the combination of cocaine and ethanol, among trauma patients who test positive for cocaine. Methods: We assembled a case series of 416 consecutive urban trauma center patients with major trauma. Urine was tested for the presence of the cocaine metabolite benzoylecgonine. Plasma was quantitatively assayed for cocaine, ethanol, and cocaethylene. Results: Of the study subjects, 158 (38%) were positive for benzoylecgonine; Of the 114 of these subjects who had adequate plasma specimens, 68 (60%) tested positive for cocaethylene (mean, 41+/-27 ng/ml; range, 3 to 213 ng/mL), all tested positive for cocaine (mean, 92.9+/-52 ng/mL), and 56% were positive for ethanol (mean, 175+/-85 mg/dL). We found poor correlation between admission levels of cocaethylene and cocaine (R=.02), even when subjects were stratified by ethanol level. The correlation between cocaethylene and ethanol levels was weak (R=.24). Of the 68 patients who tested positive for cocaethylene, 29% tested negative for ethanol. Plasma was also assayed from 94 subjects who tested negative for benzoylecgonine; 9% had detectable levels of cocaine, and 2% had detectable levels of cocaethylene. Conclusion: Cocaethylene was present in more than half of the subjects who tested positive for cocaine.