Department of Clinical Pharmacology, St. Olav University Hospital, N-7006 Trondheim, Norway.
J Anal Toxicol. 2009 Nov-Dec;33(9):610-4. doi: 10.1093/jat/33.9.610.
Differentiating new intake of drugs-of-abuse from residual drug excretion may be difficult, especially following chronic drug usage and for drugs with long elimination half-lives such as cannabis. In the present case, cannabis was found in the urine of a young pregnant woman following heavy and chronic cannabis use. She was warned that if she continued using cannabis while pregnant she would be forced to be hospitalized. She was subjected to serial urine testing with 2-7-day intervals. Urinary 11-nor-9-carboxy-Delta(9)-tetrahydrocannabinol (THCCOOH) concentrations, measured by liquid chromatography-mass spectrometry, declined from 348 to 3.9 ng/mL over a surprisingly long period of 12 weeks (84 days). Several algorithms for detecting new drug intake were applied during this time course; most indicated that the woman continued to smoke cannabis following the first urine test. The woman denied any use after the first specimen collection. In retrospect, her THCCOOH excretion profile supports her story. Algorithms for detecting new drug intake have been validated for occasional cannabis users only. We advise caution when interpreting urine test results from heavy, chronic cannabis users, especially when serious consequences are involved.
区分新摄入的毒品与残留的药物排泄可能很困难，特别是在长期吸毒和药物消除半衰期较长的情况下，如大麻。在本例中，一名年轻孕妇大量且长期吸食大麻后尿液中检测出大麻。她被警告说，如果她在怀孕期间继续使用大麻，她将被迫住院。她接受了为期 2-7 天的尿液检测。尿液中 11-去甲-9-羧基-Δ(9)-四氢大麻酚（THCCOOH）浓度通过液相色谱-质谱法测定，在令人惊讶的 12 周（84 天）内从 348 降至 3.9ng/ml。在此期间应用了几种用于检测新药物摄入的算法；大多数表明该妇女在第一次尿液检测后仍继续吸食大麻。该妇女否认第一次标本采集后有任何使用。回想起来，她的 THCCOOH 排泄情况支持了她的说法。用于检测新药物摄入的算法仅在偶尔吸食大麻的人群中得到验证。当涉及到严重后果时，我们建议在解释大量、长期吸食大麻者的尿液检测结果时要谨慎。
