A placebo-controlled study to assess Standardized Field Sobriety Tests performance during alcohol and cannabis intoxication in heavy cannabis users and accuracy of point of collection testing devices for detecting THC in oral fluid.

RATIONALE: Standardized Field Sobriety Tests (SFST) and oral fluid devices are used to screen for driving impairment and roadside drug detection, respectively. SFST have been validated for alcohol, but their sensitivity to impairment induced by other drugs is relatively unknown. The sensitivity and specificity for Δ(9)-tetrahydrocannabinol (THC) of most oral fluid devices have been low. OBJECTIVE: This study assessed the effects of smoking cannabis with and without alcohol on SFST performance. Presence of THC in oral fluid was examined with two devices (Dräger Drug Test® 5000 and Securetec Drugwipe® 5). METHODS: Twenty heavy cannabis users (15 males and 5 females; mean age, 24.3 years) participated in a double-blind, placebo-controlled study assessing percentage of impaired individuals on the SFST and the sensitivity of two oral fluid devices. Participants received alcohol doses or alcohol placebo in combination with 400 µg/kg body weight THC. We aimed to reach peak blood alcohol concentration values of 0.5 and 0.7 mg/mL. RESULTS: Cannabis was significantly related to performance on the one-leg stand (p = 0.037). Alcohol in combination with cannabis was significantly related to impairment on horizontal gaze nystagmus (p = 0.029). The Dräger Drug Test® 5000 demonstrated a high sensitivity for THC, whereas the sensitivity of the Securetec Drugwipe® 5 was low. CONCLUSIONS: SFST were mildly sensitive to impairment from cannabis in heavy users. Lack of sensitivity might be attributed to tolerance and time of testing. SFST were sensitive to both doses of alcohol. The Dräger Drug Test® 5000 appears to be a promising tool for detecting THC in oral fluid as far as correct THC detection is concerned.

Zolpidem urine excretion profiles and cross-reactivity with ELISA(®) kits in subjects using Zolpidem or Ambien(®) CR as a prescription sleep aid.

Zolpidem, a Schedule IV controlled substance under the Federal Controlled Substance Act, has a rapid onset of action and short elimination half-life, rendering it ideal as a sleep aid. The crossreactivity of two zolpidem ELISA kits was investigated using patients taking a known administration of zolpidem. Subjects provided urine samples before, 30 min after their prescribed dose, and upon waking. Specimens were screened for zolpidem by ELISA (Immunalysis and Neogen) and then confirmed and quantitated for zolpidem using gas chromatography-mass spectrometry (GC-MS) confirmation in select ion monitoring mode. All samples were measured for creatinine and corrected accordingly. The ELISA screening results demonstrated that all samples, except one, screened positive by ELISA using both kits, even when the GC-MS data found no zolpidem in the patient's urine sample. The maximum concentrations of zolpidem ranged from 15 to 120 ng/mg creatinine. Two of the patients showed zolpidem concentrations of 10 ng/mg creatinine or above after 20 h post dose. The high variability and concentration range seen in these patients, all on similar doses, suggest wide variability in the metabolism of zolpidem.

The incidence of Zolpidem use in suspected DUI drivers in Miami-Dade Florida: a comparative study using immunalysis Zolpidem ELISA KIT and gas chromatography-mass spectrometry screening.

In 1993, Zolpidem (Ambien), a non-benzodiazepine hypnotic agent, was approved for use in the United States for the short-term treatment of insomnia. Zolpidem has a rapid onset of action and short elimination half-life, rendering it ideal as a sleep aid. The objective of this study was to evaluate, and retrospectively compare, the use of the Immunalysis ELISA kit and gas chromatograpy-mass spectrometry (GC-MS) to screen blood/urine specimens for zolpidem. In addition, results for the incidence of zolpidem in suspected DUI drivers in 2007 are compared to previous years' data. The ELISA kit was evaluated for cross-reactivity with zaleplon and zopiclone and zolpidem metabolite I. Urine samples (n = 100) and blood samples (n = 100) were selected from specimens received into the DUI laboratory in 2007 and were screened via the Immunalysis Zolpidem ELISA kit and on GC-MS in full EI scan mode following an alkaline liquid-liquid extraction. Results show 5% of the urine and blood samples screened positive for zolpidem using the ELISA kits, and all 5% confirmed positive for zolpidem using GC-MS. The ELISA kit demonstrated no cross-reactivity to zaleplon or zopiclone at a spiked urine concentration of 1000 ng/mL. Ten cases of suspected DUI drivers in 2007 confirmed positive for zolpidem by ELISA and GC-MS in blood/urine, a higher incidence rate than in the previous years. Because of the low percentage elimination of the parent compound in urine, a screening method for the detection of the main metabolite of zolpidem may be needed for better detection of drug impairment driving due to zolpidem.

Immunoassay and GC-MS procedures for the analysis of drugs of abuse in meconium.

The analysis of meconium specimens for metabolites of substances of abuse is a relatively accurate method for the detection of fetal exposure to drugs. Most of the methods reported in the literature before the early 1990s relied on radioimmunoassays. The purpose of this study was to develop and validate methods for meconium sample preparation for the screening and gas chromatography-mass spectrometry (GC-MS) confirmation of meconium extracts for cannabinoids, cocaine, opiates, amphetamines, and phencyclidine. EMIT and TDx immunoassays were evaluated as screening methods. The sample preparation method developed for screening included extraction and purification prior to analysis. Cutoff levels were administratively set at 20 ng/g for 11-nor-delta9-THC-9-COOH (THCCOOH) and phencyclidine and at 200 ng/g for benzoylecgonine, morphine, and amphetamines, although lower levels could be detected in meconium using the EMIT-ETS system. Ninety-five meconium specimens were subjected to the screening procedure with GC-MS confirmation of presumptive positives. In addition, 30 (40 for cocaine) meconium specimens were subjected to GC-MS analysis for all analytes regardless of the screening results to determine the false-negative rate, if any, of the immunoassay. Although there were no false negatives detected, the GC-MS confirmation rate for the immunoassay-positive specimens was generally low, ranging from 0% for amphetamines to 75% for opiates. The lowest rate of confirmed positives was found with the cannabinoids, suggesting that tetrahydrocannabinol (THC) metabolites other than free 11-nor-9-carboxy-delta9-THC may be major contributors to the immunoassay response in meconium.

Benzodiazepines in Miami-Dade County, Florida driving under the influence (DUI) cases (1995-1998) with emphasis on Rohypnol: GC-MS confirmation, patterns of use, psychomotor impairment, and results of Florida legislation.

Benzodiazepines are central nervous system depressant drugs often detected in biological samples from driving under the influence (DUI) offenders. They are associated with marked psychomotor impairment and represent up to 20% of all Miami-Dade County, Florida DUI urine samples analyzed in our laboratory annually. Flunitrazepam emerged in the mid-1990s as an illegal drug in the U.S. that was predominantly abused recreationally and associated with sexual assaults. Immunoassays for benzodiazepines do not discriminate between different benzodiazepines, and certain metabolites, such as 7-aminoflunitrazepam, react poorly with immunoassay reagents. A simple and sensitive method for the detection and quantitation of major benzodiazepines and metabolites by gas chromatography with mass selective detection is presented. This method was used to confirm benzodiazepines in general and flunitrazepam in particular. Data collected over a three-and-a-half-year period are summarized. Whereas flunitrazepam was present in up to 10% of DUI cases in 1995 and 1996 and had fast become the most frequently encountered benzodiazepine in Miami-Dade County DUI-related urine samples, a dramatic drop in case numbers followed the legal reclassification of the drug as a Schedule I substance in Florida in February 1997. Flunitrazepam was often used alone or in combination with cannabis and cocaine. A recent rise in clonazepam cases coincides with the decrease in flunitrazepam confirmation and may indicate a new trend in the abuse of benzodiazepines in South Florida.

Recommendations for toxicological investigations of drug-facilitated sexual assaults.

The recent increase in reports of drug-facilitated sexual assaults has caused alarm in the general public and prompted forensic toxicologists from across North America to address the toxicological issues surrounding this matter. The authors have developed recommendations and guidelines to inform law enforcement, medical, and scientific personnel of the requirements for performing successful toxicological examinations in cases of drug-facilitated rape.

Plasma cocaine and tetracaine levels following application of topical anesthesia in children.

STUDY OBJECTIVES: To measure plasma cocaine and tetracaine levels in children after standardized application of a solution of tetracaine 0.5%, epinephrine 0.05%, and cocaine 11.8% (TAC) to lacerations requiring suture repair. DESIGN: Nonrandomized, controlled trial over a five-month period. SETTING: University hospital emergency department. TYPE OF PARTICIPANTS: Stable children less than 16 years of age with uncomplicated lacerations. MEASUREMENTS AND MAIN RESULTS: Blood was obtained at either 15 or 20 minutes (early; 32) or 45 or 60 minutes (late; 45) for measurement of plasma cocaine and tetracaine levels. Analysis for cocaine and tetracaine concentrations was performed using gas chromatography-mass spectroscopy with a limit of detection for both assays of 0.5 ng/mL. Serum cocaine levels were low but measurable at both times in 75% of children. No tetracaine was measurable. Median cocaine levels were 1 ng/mL (range, 0 to 112 ng/mL) for the early group and 2 ng/mL (range, 0 to 274 ng/mL) for the late group (P = NS). Only two children had levels of more than 100 ng/mL. No significant correlation between patient or laceration characteristics and cocaine levels was detected. No significant change in heart rate or blood pressure was detected. Children who required additional local anesthesia had nonfacial lacerations and lower cocaine levels than children with facial lacerations. CONCLUSION: Application of 3 mL of standard TAC solution for 15 minutes results in low but measurable plasma cocaine levels in 75% of children.

Plasma cocaine and tetracaine levels following application of topical anesthesia in a swine laceration model.

Standard TAC (0.5% tetracaine, 0.05% epinephrine, and 11.8% cocaine) solution is finding increased use as a topical anesthetic for lacerations. The extent of systemic absorption of TAC components and their resultant physiologic effects are unclear. Absorption of cocaine or tetracaine may result in serious toxicity. The investigators hypothesized that there are no measurable plasma cocaine or tetracaine levels after application of TAC in a swine laceration model. After an overnight fast 10 domestic swine underwent tracheostomy, mechanical ventilation, femoral venous, and arterial cannulation. Maintenance anesthesia with intermittent thiopental and pancuronium was provided to maintain stage III anesthesia. Heart rate (HR), arterial pressure (BP), plasma cocaine, and tetracaine levels were measured at intervals for 180 minutes. Five milliliters of TAC was applied for 15 minutes to a standardized facial laceration in experimental swine (n = 5). Randomly labeled plasma samples were placed in vials containing 2% sodium fluoride and 1% potassium oxalate, immediately refrigerated, and analyzed for cocaine and tetracaine using gas chromatography and mass spectroscopy. Significant changes in HR and mean BP, compared with baseline values, were analyzed using Dunnett's multiple range test. Plasma cocaine levels were measurable in all experimental swine after 10 minutes, while no tetracaine was detectable. No significant differences in HR or BP changes were observed between experimental and control subjects. Application of standard TAC solution results in measurable plasma cocaine levels, but not tetracaine. Further studies into anesthetic formulation, as well as timing and technique of application, are required before consensus on optimal emergency departmental use of topical anesthesia can be achieved.

Serial arsenic poisoning: two Alabama cases.

Arsenic poisoners are predominantly women. The occasional localization of cases suggests the inspiration may result from the publicity of earlier cases or word of mouth. Two recent cases of serial arsenic poisoners in Alabama are presented with discussion of the psychodynamics of the murderers.

Analysis of arsenic in forensic cases utilizing a rapid, non-ashing technique and furnace atomic absorption.

A procedure is described for analysis of arsenic in urine, hair, liver, and other biological specimens after dissolution of milligram quantities in nitric acid followed by treatment with nickel nitrate and graphite furnace atomic absorption (AA). Some data is given comparing silver diethyldithiocarbamate (AgDDC) colorimetry results to AA results. The method is fast, sensitive, and accurate. Case reports are cited.