The drug disulfiram, used for years to deter recovering alcoholics from drinking, also can treat cocaine addiction. Disulfiram prevents rats from seeking cocaine after a break, a model for addicts tempted to relapse. Disulfiram appears to work by inhibiting the enzyme dopamine beta-hydroxylase, which is required for the production of the neurotransmitter norepinephrine. A selective inhibitor of that enzyme, nepicastat, is also effective in the same model of cocaine relapse.