A model for the induction of moderate levels of methaemoglobinaemia in man using 4-dimethylaminophenol.

The induction of moderate levels of methaemoglobin by 4-dimethylaminophenol (DMAP) was studied in human and dog blood in vitro and in dogs in vivo. Although the rate of formation of methaemoglobin following intravenous injection into dogs was similar to that following addition of DMAP to dog blood in vitro, in the latter case levels fell more slowly. Addition of DMAP at the same concentrations in vitro resulted in more rapid oxidation of haemoglobin and higher peak levels of methaemoglobin in dog blood than in human blood. It was concluded that the rate of formation of methaemoglobin as well as the activity of methaemoglobin reductase must be considered when extrapolating data from the dog to man.