Although Haloperidol Decanoate (Seredol Deca) has minimal soporific action, it should be recognized that the drug can potentiate the action of the central nervous system depressants, including alcohol. High doses may potentiate the action of methyldopa as well. As with tranquilizers, it should not be used alone where depression predominates but may be combined with anti-depressants where there is associated anxiety.