Concentrations of morphine and codeine in urine of heroin abusers

We have measured concentrations of morphine, codeine and 6-monoacetylmorphine in urine of people admitted to the Los Angeles County + University of Southern California Medical Center. Of 60 patients positive for morphine and/or codeine, 10 were judged to be heroin abusers based on positive results for 6-monoacetylmorphine, a specific metabolite of heroin. In nine of these ten patients, 0.028-39.4 microg/ml free codeine and 0.070-307 microg/ml total codeine were detected along with 1.74-218 microg/ml of free morphine and 11.2-2870 microg/ml of total morphine; the morphine-to-codeine ratios were 3.65-228 and 2.27-207 for the free forms and total amounts of these opiates, respectively. In the one patient who was negative for codeine, the concentrations of free and total morphine were 0.114 and 2.22 microg/ml, respectively. Based on our data and literature data available, the following criteria are proposed for judging heroin use from the results of urinalysis, especially when no 6-monoacetylmorphine is detected: (1) a detectable amount of free morphine exists and the concentration of total morphine is higher than 10 microg/ml; (2) a detectable amount of codeine exists; and (3) the morphine-to-codeine ratio is higher than 2 for both the free forms and total amounts of these opiates.