Monitoring urine for inhaled cannabinoids

The current position on the "passive smoking" of cannabis is reviewed with particular reference to the analysis of urine. The pharmacokinetics and metabolism of delta-9-tetrahydrocannabinol are first described, followed by a survey of methods used to identify and quantify its metabolites in urine. Published data concerning the appearance of cannabinoids in urine following "passive smoking" of cannabis are compared and the most important factors described. The problems of interpreting the results of the analysis of urine in forensic cases are discussed and a possible means to clarify the position by means of analysing serum is suggested.