Urinary excretion of codeine and morphine following the administration of codeine-containing cold syrup

The concentrations of codeine ([C]) and morphine ([M]) excreted in urine obtained from nine subjects at various time intervals after the ingestion of 10-40 mg of both simple and compound codeine doses three times per day for three days were determined by gas chromatography-mass spectrometry analysis. Four distinct [C]/[M] distribution patterns (phases) were observed: a, [C] > [M] from ingestion of first dose to 78-108 h after ingestion of the first dose (18-48 h after the ingestion of the last dose); b, [C] approximately [M] 78-90 h after ingestion of the first dose (18-30 h after ingestion of the last dose); c, [C] < [M] 78-102 h after ingestion of first dose (18-42 h after ingestion of the last dose); and d, [C] <0.05 microg/mL and [M] > 0.05 microg/mL 84-96 h after ingestion of the first dose (24-36 h after ingestion of the last dose with [M] ranging from 0.10 to 0.30 microg/mL) toward the terminal phase. No single individual exhibited all four [C]/[M] distribution characteristics during the entire excretion period and intervals monitored in this study. These data are of reference value for differentiating codeine and morphine/heroin ingestion.