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.
1. In a prospective, unselective study of self-poisoned patients in 1978 and 1987 blood samples for drug analyses were drawn on admission in 265 and 400 cases, respectively. 2. The results from the drug analyses were compared with the clinical information obtained on admission. The main drug taken was identified on admission in 228 (86%) in 1978 and in 383 cases (96%) in 1987 (P < 0.001). 3. The clinical impression was completely in accordance with the results from the drug analyses in 192 cases (72%) in 1978 and 232 cases (58%) cases in 1987 (P < 0.001). The discrepancies mainly involved secondary drugs. 4. There was no significant difference in the clinical course of the poisonings in situations where the correct main drug was identified on admission and where the wrong main drug was suspected. 5. Knowledge of the correct drugs used when admitted would not have prevented complications or deaths. 6. We conclude that extensive pharmacological drug analyses play a limited role in the routine management of patients admitted for deliberate self-poisoning.
Intoxications with the antifreeze constituent ethylene glycol (EG) occur infrequently, but may be fatal if not recognized and treated promptly. The aim of the present work was to develop an analytical method for rapid diagnosis of EG poisoning and for monitoring EG removal by hemodialysis. EG was measured by gas chromatography upon direct injection of serum or urine samples (50 microL diluted in 200 microL of distilled water containing 2,3-butanediol as internal standard). A 2-m x 2-mm glass column with Chromosorb 101 (80/100 mesh) separates these glycols within four minutes at 200 degrees C, using nitrogen as the carrier gas. The glycols 1,2- and 1,3-propanediol were separated from EG and the internal standard. Acetone, methanol, and isopropanol did not interfere with the analysis. The limit of quantitation of EG was close to 0.5 mM. Because no derivatization, extraction, or concentration procedures were necessary, EG may be determined quantitatively within 30 min, allowing for monitoring of hemodialysis, which should be performed for 15 h in severe cases. The diagnosis of ethylene glycol intoxication in a late stage may be secured by analysis of urine collected on admission.
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