ANALYTICAL CHEMISTRY AT FORENSIC INSTITUTES 63 CHIMIA 2002, 56, No. 3 Chimia 56 (2002) 63–65 © Schweizerische Chemische Gesellschaft ISSN 0009–4293 Drugs and Driving: Analytical Strategy Marc Augsburger* Abstract: Consumption of psychoactive substances may impair driving performance. Because of the diversity of the substances, toxicologists have to develop analytical strategies which allow the detection and the quantification of drugs in biological samples. The analytical strategy described here is composed of three steps: screening, confirmation, and quantification. For screening, immunological tests and chromatography techniques (GC and HPLC) are often used. For confirmation, identification by means of mass spectrometry is required, and quantification is often realized through chromatographic techniques. Keywords: Driving under the influence of drugs (DUID) · Forensics · Gas chromatography · Immunoassays · Liquid chromatography · Mass spectrometry Introduction ton of Vaud, the same results were ob- these two situations. In order to help the served [2]. Moreover, methadone, which judge to demonstrate driving incapacity , Consumption of legal or illegal psycho- is frequently used as a heroin substitute in forensic analysis has to determine wheth- active substances has become very com- Switzerland for narcotic maintenance er the subject was under the influence of mon in our society, and an increase in the treatment of former opiate addicts, was drugs which could impair driving capaci- consumption of these substances can be never found as the sole drug present. The ty at the time of the event (police con- observed. On the other hand, road traffic high incidence of interaction for metha- trol, crash, ...). The only possibility to is increasing continuously. Because of done cases suggests that driving impair- find an answer through forensic analysis the extent of these two social phenomena, ment of patients under methadone-substi- is to quantify the drugs in the blood. In it is not surprising that driving under the tution treatment should be evaluated case of inaptitude, forensic analysis has influence of drugs is gaining in signifi- carefully considering that methadone to help the administration to evaluate the cance for the health, political, juridical, side effects could be increased by inter- dependence on certain drugs. In this con- and administrative authorities. It is well action with other drugs. The prevalence text, urine and hair are the matrices of known that the effects of alcohol can im- of drug use in combination with alcohol choice for the analysis because of their pair driving. Therefore, it seems justified is frequently reported in the different large window of detection. However, for to wonder if some crashes or aberrant at- studies included in the overall survey of alcohol, blood is widely used for labora- titudes could be explained by impairment the Council of Europe [1]. This survey tory diagnosis of chronic alcohol abuse due to consumption of psychoactive sub- emphasized also that higher accident risk by the determination of carbohydrate- stances such as cannabis, opiates, co- in the event of multiple drug use is a deficient transferrin (CDT) or other caine, amphetamines, benzodiazepines, reflection of the clear synergistic inter- markers [3]. LSD, or tranquilizers. action of alcohol and drugs, if mortality In most surveys reported in different is taken as the outcome variable. Conse- European countries cannabinoids are the quently, the analytical strategy set up for Substances most frequently detected illicit drugs [1]. the evaluation of the driving impairment In general the use of opiates is less fre- due to the consumption of drugs must As suggested by one group of the quently observed in driver populations screen a wide variety of drugs which are Council of Europe (Pompidou group) [1], than the use of cannabis. The most fre- suspected of decreasing driving perform- it seems unacceptable to base a reasoned quently detected licit drugs in all driver ance. argument about drugs and road safety on populations are the benzodiazepines. In a Impairment due to drug consumption an over-simplified distinction between survey concerning the nature of the drugs can be observed in two different situa- licit and illicit drugs. It is not the classi- used among drivers suspected of driving tions. On the one hand, impairment is due fication which matters, but the use to under the influence of drugs in the Can- to a single dose of drug. The effects of the which such substances are put. A lot of drug consumption involve transitional psychopharmacological studies have re- impairment of driving performance (in- vealed the adverse effects of many drugs *Correspondence: Dr. M. Augsburger capacity). On the other hand, impairment on driving performance. On the basis Institut Universitaire de Médecine Légale can also be due to chronic consumption of current knowledge, the psychotropic Laboratoire de Toxicologie Analytique of a drug, involving drug dependence. drugs which are capable of producing Rue du Bugnon 21 CH–1005 Lausanne In this case, driving performance is im- driving impairment are: anesthetics, Tel.: + 41 21 314 70 70 paired on a long-term basis (inaptitude). antidepressants, antihistamines, canna- Fax: + 41 21 314 70 90 E-Mail: [email protected] The analytical strategy is different in binoids, cardiovasculars, hallucinogens, ANALYTICAL CHEMISTRY AT FORENSIC INSTITUTES 64 CHIMIA 2002, 56, No. 3 hypnotics, narcotics, psychomimetics, sedatives, solvents, stimulants, and vola- Screenings tiles. The challenge for the analytical toxicologist is to develop a sensitive (immunoassays, GC-FID/NPD/MS, HPLC-DAD) screening which can be used for the detection of the majority of these psycho- tropic drugs. In case of licit drug prescription, there Confirmation & identification is no doubt that some medications cause drowsiness for some patients. However, (GC-MS, HPLC-MS/DAD) drowsiness could be a desired therapeutic goal without side-effects and depend upon the situation and the indication for Quantification which a drug is prescribed. If the patient wants to sleep during the night, drow- (GC-FID/NPD/ECD/MS, HPLC-MS/DAD/fluorescence) siness is a desired effect; but during day- time it could adversely affect the alert- Fig. Analytical strategy for biological sample analysis for the determination of driving impairment ness of a car driver. Moreover, it must be due to drug consumption. remembered that patients for whom a tranquilizer is prescribed to treat anxiety Saliva has been proposed as a speci- illicit drugs, to obtain a driving license or aggressiveness, or depressed patients men for roadside tests. However, the con- [5]. who take some antidepressants, are cer- centration of drug in the saliva specimen For fatally injured drivers it is recom- tainly safer drivers after they have re- will depend on the type of saliva, whether mended that blood be collected from the ceived their medication. it is true parotid saliva or not, on the pH femoral vein at autopsy, because in the of salivary flow, on salivary flow stimu- case of weakly basic drugs such as the tri- lation, and on the plasma protein binding cyclic antidepressants, concentrations in Matrices of the drug or metabolite. Under certain cardiac and sub-clavian blood increase conditions (e.g. standardized saliva col- after the death. Moreover, other speci- Analysis of blood, urine, saliva or hair lection, development of specific immu- mens such as gastric content, vitreous gives different information (Table 1). noassays for saliva) saliva will play an humor, liver or bile are available, and Blood has been considered to be the only important role for the recognition on the may complete information. suitable specimen. This is obviously true, road by the police of driving impairment because available pharmacological data due to drug consumption. An earlier use attempt to correlate plasma concentra- of saliva testing was conducted by Peel et Analytical Strategy and tions to either therapeutic or impairment al. (1984) [4]. Fifty-six saliva samples Analytical Tools effects. The detection of a drug and/or its from 445 suspected drivers were ana- metabolites in blood is evidence of recent lyzed for the presence of cannabinoids, Laboratories have often adopted an use and therefore of a potentially impair- volatiles and benzodiazepines using an analytical strategy composed of three ing effect. However, some drugs and immunoassay technique and GC/MS for steps (Fig.): their metabolites can be detected for ex- confirmation. The authors concluded that a) general unknown analysis in order to tended periods in blood after either acute the use of saliva was a potentially versa- determine the presence of drugs in the or chronic dosing. Urine is probably the tile noninvasive technique. samples; specimen of choice for additional infor- Although some techniques have been b) specific identification of the drugs; mation and hair analysis can represent a examined which test hair samples, the c) quantification of drugs in blood sam- powerful tool to estimate the historical consensus of opinion indicates that they ples and urine. aspect of the situation. Urine is preferred are not reliable due to the inconsistent re- Different analytical tools can be used for screening since drug concentrations lationship between results and recent for the first step. Methods for the deter- are usually higher and can be detected for drug ingestion. However, hair analysis is mination of the presence of drugs