In Spain today, the presence of drugs in saliva is considered sufficient to confirm driving under its
effects, although the concentration obtained is near the threshold limits of the analytic system. This
legal approach entails accepting that there is no concentration threshold below which the drug does
not affect driving capacity, and that oral fluid concentration is a reliable parameter to value its effect.
In the case of cannabis, some experimental studies in humans and in intercepted drivers have suggested
blood tetrahydrocannabinol concentrations from which effects that can affect driving are
observed. Furthermore, correlation between tetrahydrocannabinol concentration in oral fluid and
in blood shows a high variability. To resolve disagreement between these types of samples, some
countries have harmonized their legislation establishing presumptive oral fluid cannabis values at
the same time as blood concentration limit values from which it can be clearly considered that
driving capacities are affected. In this work, we consider that the Spanish road safety law should,
following trends adopted by other countries, establish a limit value for cannabis and other abused
drugs, which allows evidence that the driver has not only consumed the drug, but is also driving
under its effects.
Authors
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Núria Boix Sabrià - Unidad de Toxicología. Departamento de Farmacología, Toxicología y Química Terapéutica. Facultad de Farmacia y Ciencias de la Alimentación. Universitat de Barcelona. España
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Eva María Bajo-Tobio - **Instituto de Medicina Legal Las Palmas, Consejería de Presidencia, Justicia e Igualdad. Gobierno de Canarias. España
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Jesús Gómez-Catalán - Unidad de Toxicología. Departamento de Farmacología, Toxicología y Química Terapéutica. Facultad de Farmacia y Ciencias de la Alimentación. Universitat de Barcelona. España
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Miguel Rodamilans Pérez - Unidad de Toxicología. Departamento de Farmacología, Toxicología y Química Terapéutica. Facultad de Farmacia y Ciencias de la Alimentación. Universitat de Barcelona. España
Keywords:
Cannabis; Driving; Blood; Saliva.