Metabolism of trichloroethylene in man. III. Interaction of trichloroethylene and ethanol.

Volunteers inhaled a constant concentration of 50 ppm trichloroethylene (Tri) for 6 hrs per day on 5 consecutive days. Simultaneous ethanol (EtOH) ingestion (blood level 0.6%) inhibits the metabolization of Tri to trichloroethanol (TCE) and trichloroacetic acid (TCA) by 40% on the average. Oxidation of Tri to TCA does not occur as long as EtOH is present. During this time period the blood Tri-concentration increases 2 1/2-fold, that in the expired air rising 4-fold, as compared to Tri inhalation without EtOH. TCE glucuronidation is not subject to inhibition. On concurrent inhalation of Tri, the EtOH and acetaldehyde levels are slightly increased over the control values without Tri. The mechanisms underlying the alternate inhibition of mixed-function oxygenases and aldehyde dehydrogenase on simultaneous intake of Tri and EtOH are discussed. The intolerance reaction occurring on combined exposure to Tri and EtOH can be interpreted as an accumulation of Tri in the CNS resulting from the complete depression of Tri oxidation.