It is accepted that psychotropic drugs may be associated with motor vehicle accidents. Approaches that could clarify the influence of drugs on driving skills include prospective experimentation with human volunteers and patients in laboratory and actual driving situations and epidemiological studies in which the use of drugs among drivers is being studied. The epidemiological approach appeals to roadside surveys. To determine the incidence of drug use in driver impairment blood samples are needed. The examination of the legal limit for blood alcohol in the case of suspection of driving under the influence of alcohol, mostly provides the opportunity to analyse a blood sample on drugs too. However, the use of blood samples decreases by the increased use of breathanalyzers. During drug screening in blood samples any measurable amount of drug is accepted for statistical and medico-legal purposes. However, the precise meaning of such drug concentrations relative to driver impairment is not clear. There is in fact a wide variation in response to standard dosages of psychoactive drugs. This variation is partly due to remarkable interindividual differences in drug disposition in the body; e.g. protein binding and the presence of pharmacological active metabolites. Measuring drug concentrations in plasma means a total drug concentration not the free concentration in equilibrium with the site of action in the body. The concentration of most drugs in saliva corresponds to the free concentration of the drug in plasma. Furthermore, saliva can be obtained by non-invasive techniques even without medical assistance. For these reasons the use of saliva analyses is suggested in epidemiological and field studies. For road side surveys simple qualitative methods of analysis and screening techniques for drugs in saliva need to be developed. In this way only confirmed positives may be quantitated using specific and sensitive analytical procedures. The latter is only sensible when the precise meaning of such drug concentrations relative to driver impairment is clear.

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 197-202

Subject/Index Terms

Filing Info

  • Accession Number: 00396594
  • Record Type: Publication
  • Source Agency: National Highway Traffic Safety Administration
  • Report/Paper Numbers: HS-037 597
  • Files: HSL, USDOT
  • Created Date: Aug 31 1985 12:00AM