Vasoactive drugs have been suggested to modulate the cytotoxicity of chemotherapy and radiotherapy. In this study, we have tested whether a number of commonly used vasoactive drugs interact with epirubicin- and radiation-induced toxicity on Chinese hamster fibroblast cell line V-79. The adrenoceptor agonist epinephrine, enchanced die effects of irradiation as measured by cloning capacity. In contrast, epineprine and terbutaline decreased epirubicin cytotoxicity. The beta-adrenoceptor antagonist propranolol and the alpha-antagonist phentolamine, at 100 mumol/l, caused a significant enhancement of epirubicin cytotoxicity. None of the vasoactive drugs showed intrinsic cytotoxic effects. Radiation-induced cytotoxicity was unaffected by propranolol or phentolamine. The calcium channel blocker, verapamil, enhanced the toxicity induced by epirubicin and radiation. These results indicate that vasoactive drugs such as epinephrine, propranolol and phentolamine can interfere with radiotherapy and with anthracycline cytotoxicity. Further studies are warranted before conclusions on the mechanisms of action can be drawn.

Related Articles