It is necessary to pay attention to drug interactions that influence the pharmacokinetics of anticancer drugs used for chemotherapy because the therapeutic window of such drugs is narrow. However, very few studies have been done on potential interactions with anticancer drugs used for chemotherapy.
We therefore analyzed information on drug interactions among patients undergoing cancer chemotherapy at JA Aichi Kouseiren Atsumi Hospital. More than half of the registered chemotherapy regimens included anticancer agents that have contraindicated drugs and all of the regimens included anticancer agents that have significant drug interactions. Logisticregression analysis showed that the risks of “unintended drug interactions”, drug interactions other than those due to additive or synergistic effects expected from the combination of drugs administered for cancer chemotherapy and palliative care therapy, were enhanced by increases in the numbers of concomitant drugs and drugs prescribed by other clinics being taken by patients.
In conclusion, there are a large number of potential drug interactions in cancer chemotherapy and many are clinically important. Our findings indicate that attention should be paid to unintended drug interactions with regimens that include diphenhydramine or anticancer drugs that are metabolized by cytochrome P450 (CYP), as well as when antihypertensive drugs, antidiabetic drugs or central nervous system suppressants are being taken concomitantly.
