Experimentally induced toxic-haemolytic anaemia in laboratory rats following phenacetin administration

In an attempt to give assistance in the search for a simple haematological system for the detection of toxic-haemolytic effects of chemical substances, we used a battery of simple tests and phenacetin as a reference substance. The drug was administered in a single dose or repeatedly for two or four weeks. Higher plasma haemoglobin levels and symptoms of anaemia (decreased blood haemoglobin levels, erythrocytic counts, haematocrit) and activated erythropoiesis (increased reticulocyte counts, MCV, marrow and splenic E:M ratios) were found to be best marked following administration of phenacetin in the very high dose of 1.0 g/kg per orally for two weeks. Our results suggest that plasma haemoglobin levels could provide information on the haemolytic potential of phenacetin if the experimental schedule included the optimal combination of suitable phenacetin dosage and duration of loading.