Reduction of anthracycline cardiotoxicity by amrinone and sulmazole

In attempts to alleviate or prevent anthracycline toxicity, we have recently reported that amrinone and sulmazole markedly reduce the negative inotropic effect of adriamycin and 4-epiadriamycin in isolated spontaneously beating guinea pig atria in normodynamic or hypodynamic conditions. Amrinone and sulmazole are non catecholamine, non glycoside agents with inotropic properties. The present study reports the effects of adriamycin and 4-epiadriamycin (100 micrograms/ml) on electrically driven isolated guinea pig left atrium in normodynamic or hypodynamic conditions. Exposure for 60' to the two drugs caused a depression of contractile force and of maximal rate of contractile force (df/dt). The cardiac depressant effect of adriamycin as shown previously on spontaneously beating atria does not differ from that of 4-epiadriamycin. The negative effects of the two antitumor drugs are antagonized by amrinone (200 micrograms/ml) and sulmazole (100 micrograms/ml).