Cancer patients are increasingly benefiting from new treatment strategies and advances in supportive care. However, adverse drug interactions of anticancer agents are a major cause of morbidity and mortality, and cancer patients are at particularly high risk of such interactions because they commonly receive multiple medications. In addition, the majority of cancer patients are elderly, and the ages-related decline in hepatic and renal function reduces their ability to metabolize and clear drugs and increase the potential for toxicity.
Drugs interaction can be categorized as pharmaceutical, pharmacodynamic, or pharmacokinetic. Pharmaceutical interactions may occur when two compounds interact because they are incompatible either physically or chemically. These may also occur as the modulating effect of a vehicle on the pharmacokinetic and pharmacodynamic properties of drugs. Pharmacodynamic interactions may occur when two or more drugs have mechanisms of action that influence the same physical process. Excessive response and increased toxic effects are seen if the interaction is additive or agonistic. When drugs have an antagonistic effect, the drug can decrease and the patient's response to the drug can be reduced. Pharmacokinetic interactions may occur when one drug influences the absorption, distribution, metabolism, and/or excretion of another. Metabolizing enzyme or drug transporters are often involved in these processes. The hepatic CYP system is the major site of drug metabolism, and most drug interactions take place at this site. P-glycoprotein is a membrane-bound protein, and has an important influence on the management of cancer patients due to this ability to transport antineoplastic agents out of cancer cells.
Drugs interactions of antineoplastic agents, supportive car medications, and/or drugs to treat co-morbid conditions will be introduced in this session. The adverse drugs interaction should be minimized by considering the potential for interactions of all the drugs that cancer patients are receiving.