Effects of consumption of ethanol on the biological monitoring of exposure to organic solvent vapours: a simulation study with trichloroethylene.

This study illustrates possible influences of consumption of ethanol on the pharmacokinetic behaviour of inhaled trichloroethylene (TRI) in relation to biological monitoring of exposure. The results were obtained for a standard male worker of 70 kg by physiologically based pharmacokinetic modelling. Depending on the pattern of consumption of ethanol, enzyme inhibition or induction was assumed to prevail in this worker. The inhibition and induction were modelled by assuming competitive metabolic interaction between TRI and ethanol and increased maximum velocity (Vmax) of TRI metabolism respectively. Ingestion of moderate amounts of ethanol before the start of work or at lunch time, but not at the end of work, caused pronounced increases in blood TRI concentrations and decreases in the urinary excretion rates of TRI metabolites, this effect lasting until the next day. The effects were smaller the higher the exposure concentration of TRI. Induction of TRI metabolism, supposedly by consumption of ethanol the previous evening, caused only small changes in the pharmacokinetic profile at 50 ppm, but appreciable changes at 500 ppm.