[Observations in phenprocoumon (Marcumar) poisoning. Elimination and serum binding of the anticoagulant atatoxic blood concentration].

Serial serum concentrations of phenprocoumon were measured in 2 female patients who had taken 150 and 450 mg of the drug in suicidal attempts. In one case absorption of phenprocoumon took nearly two days. At a concentration of 1.7 and 1.8 microgram/ml the elimination curve showed a notch in both patients. Above this concentration half life was 97.7 and 95.9 hours, below these levels 134.4 and 155.5 hours. In-vitro binding investigations with serum of a healthy proband showed an increase of the non-bound drug by 56.6% at a phenprocoumon concentration of 0.5-25.34 micrograms/ml. As no notch could be observed at lower concentrations the notch in the elimination curve cannot be explained by concentration-dependent plasma binding of the anticoagulant. In-vitro experiments involving haemodialysis indicate that the letter cannot be recommended for treatment of phenprocoumon intoxication as the amount of phenprocoumon thus eliminated from the body is minimal. Both patients survived the phenprocoumon intoxication without damage. They were only treated with vitamin K.