With increasing age, the incidence of neoplastic disease and the likelihood of receiving multiple prescriptions increases. Antineoplastic drugs generally have a narrow therapeutic index and are delivered at doses close to toxic. Thus, a slight increase of the biological activity caused by an interaction with simultaneously delivered drugs could be deleterious for the patient. This article summarizes the known pharmacological interactions with quinoid anticancer drugs of some during antitumor therapy commonly used drugs. The effect of antiemetics (chlorpromazine, dixyrazin, droperidol, metoclopramide), and antimicrobial agents (piperacillin, sulfamethoxazole, benzylpenicillin, amphotericin B), and adrenoceptor antagonists (propranolol, metoprolol, phentolamine) on epirubicin-induced fibroblast toxicity as studied by clonogenic survival and DNA-precipitation assay is described.