[Immunotherapy of drug poisoning]

Immunotherapy of drug intoxications is based on intravenous administration of antibodies or antibody Fab fragments specific to a drug. Mechanism of action involves toxin complexation in the antibody distribution space resulting in a gradient efflux of the toxin from its binding site by dissociation of toxin-receptor to the vascular space. Reversal of toxic effects by specific Fab fragments has been demonstrated experimentally for digitalis, colchicine and tricyclic antidepressants. The intravenous administration of antibodies or Fab fragments alters toxin pharmacokinetics including tissular depletion, plasma redistribution and decrease of systemic clearance. Benefit of this therapy in clinical toxicology has been clearly shown for cardiac glycosides but has to be confirmed for colchicine and tricyclic antidepressants. Safety and efficacy of specific Fab fragments should permit an extension of this antidotal procedure towards other toxins.