Potentiation of the toxicity of adriamycin by propranolol.

Both propranolol and adriamycin are biochemically known to inhibit mitochondrial CoQ10-enzymes of myocardial tissue in vitro. Both propranolol and adriamycin are clinically known to cause cardiotoxicity. At two dose levels of propranolol which caused no deaths to mice when administered alone, significant potentiation (p less than 0.01) of the lethality of adriamycin to mice was observed. These data, projected to the clinical situation, seem to contraindicate the administration of the beta-blocker, propranolol, for the hypertension of a cancer patient who is being treated with adriamycin.