[Clinical implications of undesirable consequences of antineoplastic drug interactions]

The fundamental objective of treating patients with tumor disease is to destroy the largest possible number of neoplastic cells, simultaneously minimizing toxicogenic after--effects. Currently there are approximately 60 drugs that are used in treatment of various types of tumors. They are chemical compounds varying in respect of both their origin and action. Most of them are substances which damage the DNA of a neoplastic cell. With chemotherapy the most important issue is to administer to patients the maximum amount of medicine in the shortest intervals possible. Nevertheless, we must first of all bear in mind that there exist undesirable drug interactions which may radically alter a chemical treatment objective. It is a commonly known fact that reducing doses of medicine involves the failure of chemical treatment. The failure of a chemical treatment may also be connected with a decrease in anti-neoplastic activity or with an increase in toxicity of anti-neoplastic drugs. A number of most clinically important unfavourable interactions between commonly applied drugs and cytostatics are presented in this article. It is crucial issue to become acquainted with all the undesirable interactions in applying chemotherapy, since the lack of knowledge in this area may result in mishandling the chance of recovery.