INFLUENCE OF ANTIMALARIALS CHLOROQUINE, QUININE, PRIMAQUINE AND MEPACRINE ON THE EVOLUTION OF EHRLICH ASCITES TUMOR

Substances like imidazoles, benzimidazoles and also quinolines, whose chemical structure includes a heterocyclic nitrogen, are known to inte rfere with the microsomal oxidation and, in some cases, with the metab olism of drugs. Since chloroquine and primaquine exert this effect in vivo and in vitro, we studied the influence of other antimalarials (qu inine and mepacrine) in mice with induced Ehrlich ascites tumour (EAT) to find out whether variations in oxygen consumption affected the cou rse of the disease. In vitro data, obtained by a polarographic techniq ue, indicate that primaquine and, in particular, mepacrine increase EA T-cell oxygen consumption, while in vivo data, obtained in mice inject ed with an inoculum of about 1 x 10(6) tumour cells per mouse, show th at both drugs, but notably mepacrine, accelerate tumour growth, as mon itored by Cox's statistical method for body weight, and lead to earlie r death. In cases of existing neoplasia, therefore, the potentially to xic effects of certain antimalarials must be borne in mind.