Disulfiram and erythrocyte aldehyde dehydrogenase inhibition.

During disulfiram therapy erythrocyte aldehyde dehydrogenase (ALDH) was fully inhibited. The time for total loss of erythrocyte ALDH activity ranged from 36 to 120 hr. In contrast to the 85% recovery of in vitro disulfiram-inhibited ALDH activity, this in vivo disulfiram-ALDH inhibition could not be reversed by mercaptoethanol. It is proposed that the in vivo and in vitro mechanisms of ALDH inhibition by disulfiram differ. Erythrocyte ALDH activity can be readily monitored to determine patient compliance and is an accessible model for investigations of in vivo mechanisms of drug inhibition. Because the disulfiram-inhibited erythrocyte ALDH is not regenerated until new erythrocytes are made (120 days), a significant portion of the extrahepatic acetaldehyde metabolic capacity remains inhibited for long periods after disulfiram is discontinued. Thus, the recidivistic patient who discontinues disulfiram and waits several days (to regenerate liver ALDH activity) before drinking will be exposed to even higher ethanol-derived blood acetaldehyde levels than usual, which may induce further alcohol-associated organ damage and alcohol dependence.