Blood, urine, and breath levels after rapid intravenous infusion of ethanol

Urine as a Biological Specimen for Forensic Analysis of Alcohol and Variability in the Urine-to-Blood Relationship

This article concerns the use of urine as a biological specimen for determination of alcohol in clinical and forensic toxicology and discusses factors that might influence variability in the urine/blood concentration ratio of alcohol. A large number of human drinking experiments were conducted to determine the time course of urine-alcohol concentrations (UAC) in relation to blood-alcohol concentrations (BAC). The UAC and BAC curves were shifted in time and the BAC curve always began to decrease before the UAC started to decline. During the early absorption phase the UAC/BAC ratio was less than unity, whereas in the late absorption/distribution period the ratio was between 1.0-1.2. On reaching the post-absorptive phase, the UAC always exceeded BAC and UAC/BAC ratios averaged 1.3-1.4, increasing appreciably as BAC decreased towards zero. Alcohol-induced diuresis was most pronounced during the rising portion of the BAC curve and near to the peak value. After about 2 hours post-drinking, the production rate of urine diminished to the pre-drinking rate of about 0.5-1 mL/min. Drinking water during the post-absorptive phase of the alcohol curve produced dilute urine, as reflected in lower creatinine content and osmolality, although the concentration of ethanol remained unchanged. After subjects drank a moderate dose of ethanol (0.54-0.85 g/kg) about 2% of the dose was recoverable in the urine after 7 hours. Ethyl glucuronide, a minor metabolite of ethanol, was measured in urine samples from drunk drivers. The UAC/BAC ratio of ethanol in drunk drivers did not depend on the creatinine content of the urine and therefore the relative dilution of the specimens. When alcohol-free urine was spiked with glucose and infected with the yeast species Candida albicans, ethanol was produced by fermentation after approximately 24 hours storage at room temperature. This post-sampling synthesis of ethanol was prevented by sodium fluoride (1% weight by volume) in the urine tubes or by keeping the specimens in the cold (4 degrees C). The UAC and BAC were highly correlated (r > 0.95) in drunk drivers and in autopsy cases, although the residual standard deviations were appreciable. This speaks against attempting to estimate BAC indirectly from UAC in any individual case. The UAC/BAC ratio and the change in UAC between two successive voids can help to resolve whether a large amount of alcohol had recently been consumed. This information is useful to support or challenge allegations of drinking alcohol after driving, which has become known as the hip-flask defence.

Interindividual variations in the disposition and metabolism of ethanol in healthy men

Forty-eight healthy men each drank a dose of ethanol, 0.68 g/kg of body weight, as neat whisky at about 09.00, after fasting overnight. The drink was finished within 20 min and the concentrations of ethanol in samples of capillary blood were determined at 30-60 min intervals for 7 hr. Rectilinear regression lines were fitted to the elimination phase of blood concentration time profiles and blood-ethanol parameters were calculated as described by Widmark. In 23, 14, 8 and 3 subjects the peak blood ethanol concentrations were reached at 30, 60, 90 and 120 min timed from starting to drink. The highest concentration of ethanol in blood was 0.92 +/- 0.022 mg/ml (mean +/- SE) and the coefficient of variation (CV) was 16.8%. The blood concentration of ethanol extrapolated to zero-time was 0.98 +/- 0.009 mg/ml (CV = 6.5%) and the apparent volume of distribution (Vd) was 0.695 +/- 0.0064 L/kg (CV = 6.4%). The rate of ethanol elimination from blood was 0.126 +/- 0.0018 mg/ml/hr (CV = 9.9%) and the body clearance was 87.5 +/- 1.1 mg/kg/hr (CV = 8.7%). The apparent volume of distribution of ethanol was inversely related to the subject's body weight (r = -0.59 +/- 0.118, p less than 0.001). The elimination rate from blood was lower in those subjects with larger distribution volume; the parameters were negatively correlated (r = -0.52 +/- 0.126, p less than 0.001). The results show that blood-ethanol parameters calculated according to Widmark's method have low intersubject variability when the dose of ethanol administered and the condition of the test subjects are carefully controlled.(ABSTRACT TRUNCATED AT 250 WORDS)

The pharmacokinetics of alcohol in human breath, venous and arterial blood after oral ingestion

The concentration-time profile of ethanol in breath air (AAC), arterial (ABAC) and venous blood (VBAC) of human volunteers was studied after four different oral doses of absolute alcohol--0.5, 0.75, 1.0, and 1.25 g/kg body weight. Seventy-eight single dose experiments were carried out in 42 subjects. In all 78 studies AAC was measured and VBAC was estimated simultaneously in blood collected from a cubital vein of 36 volunteers. Arterial blood, too, was collected from 8 subjects from a catheter in a brachial artery. All blood alcohol concentrations were analysed independently by gas chromatography (GLC) and an enzymatic (ADH) method. A one-compartment open model with first order absorption and pseudo-zero-order elimination was employed to calculate the pharmacokinetic parameters. The average values for the first order absorption rate constant (ka) ranged from 2.2 to 3.1, from 2.4 to 2.6 and from 1.0 to 1.7 h-1 for ACC, ABAC and VBAC, respectively. The pseudo-zero-order elimination rate constant (beta) was 0.17 to 0.18, 0.21 to 0.22 and 0.26 to 0.27 g X 1(-1) X h-1, respectively. During absorption ABAC tended to be higher than VBAC, peaking at a higher level (Cmax) and with a shorter time to peak (tmax) until an arterio-venous concentration equilibrium was reached, whereafter VBAC remained above ABAC. Although there was a close relationship between AAC, ABAC and VBAC during elimination, AAC closely followed the pattern of ABAC during absorption and tended to deviate from VBAC. AAC, therefore, is a much better predictor of ABAC during absorption than VBAC.

A collection of therapeutic, toxic and fatal blood drug concentrations in man

In order to assess the significance of drug concentrations measured in clinical and toxicological investigations, it is essential that good collections of data are readily available. As a guide to interpreting findings, the present work provides a compilation of therapeutic, toxic and fatal blood concentration ranges of 298 drugs of interest to clinical pharmacologists, clinical toxicologists, and forensic toxicologists. Wherever possible, ranges are expressed concisely in terms of the maximum blood concentrations which account for 10, 50 and 90% of the data collected. They provide easy access to the most reliable information which relates the blood drug concentration to the biological response it produces. Where appropriate, the different toxic effects of a drug and/or the different degrees of severity of toxic symptoms associated with different drug levels are clearly defined. The original sources of all data used are provided to allow the analyst to obtain further analytical, pharmacokinetic and toxicological information should this be necessary. Those factors (e.g. age, capacity for drug metabolism, drug interactions, etc) which can modify the relationship between a drug concentration and the response it produces are briefly discussed.

A new blood-flow pharmacokinetic model for ethanol

A multicompartmental mathematical model, taking into account observed vascular concentration gradients and blood flow rate limitations, has been proposed. Based on blood flows and blood and tissue volumes reported in the literature and in personal communications, an appropriate model was elaborated for ethanol in the dog. The relatively high values of r2 and a correlation coefficient determined for the simultaneous computer fitting of mean observed blood ethanol concentration, time data from two administered doses, support the proposed model. While the surgery is prohibitive for human experimentation, correlations may be extended to man. The elaboration of a more complete multicompartmental model for ethanol should prove beneficial in revealing the relationships among the doses of alcohol, the circulating blood ethanol concentrations, and physiological and psychomotor test parameters.

Nonlinear pharmacokinetics of ethanol: the disproportionate AUC-dose relationship

Whole venous blood concentrations of ethyl alcohol were measured following the constant rate intravenous infusion of ethanol to four Beagle dogs. Five different doses (0.1-0.8 g ethanol/kg body weight) were administered at scheduled intervals. The area under the blood ethanol concentration-time curves (AUC) was found to demonstrate a markedly nonlinear relationship with the administered dose. Simulations of one and two compartment open models with Michaelis-Menten elimination kinetics and zero-order input are presented with their theoretical AUC-dose relationships.