Concentrations of unconjugated morphine, codeine and 6-acetylmorphine in urine specimens from suspected drugged drivers.

Concentrations of unconjugated morphine, codeine and 6-acetylmorphine (6-AM), the specific metabolite of heroin, were determined in urine specimens from 339 individuals apprehended for driving under the influence of drugs (DUID) in Sweden. After an initial screening analysis by immunoassay for 5-classes of abused drugs (opiates, cannabinoids, amphetamine analogs, cocaine metabolite and benzodiazepines), all positive specimens were verified by more specific methods. Opiates and other illicit drugs were analyzed by isotope-dilution gas chromatography-mass spectrometry (GC-MS). The limits of quantitation for morphine, codeine and 6-AM in urine were 20 ng/mL. Calibration plots included an upper concentration limit of 1000 ng/mL for each opiate. We identified the heroin metabolite 6-AM in 212 urine specimens (62%) at concentrations ranging from 20 ng/mL to > 1000 ng/mL. The concentration of 6-AM exceeded 1000 ng/mL in 79 cases (37%) and 31 cases (15%) were between 20 and 99 ng/mL. When 6-AM was present in urine the concentration of morphine was above 1000 ng/mL in 196 cases (92%). The concentrations of codeine in these same urine specimens were more evenly distributed with 35% being above 1000 ng/mL and 21% below 100 ng/mL. These results give a clear picture of the concentrations of unconjugated morphine, codeine and 6-acetylmorphine that can be expected in opiate-positive urine specimens from individuals apprehended for DUID after taking heroin.