Drug Interactions in Palliative Cancer Care and Oncology

As palliative care expands into the outpatient clinic, the potential for drug interactions increases as patients that are on active treatment for their cancer are also receiving coordinated management for symptoms such as pain, depression, and nausea and vomiting. The drugs used in inpatient palliative care for patients with advanced illness but not on active management of their malignancy must now be reviewed for potential interactions with both older and newer oncology drugs. Reported frequencies of drug interactions in oncology range from 12 to 63 %; and in palliative care they range from 31 to 43 %. Among the drugs which are most likely to cause interactions, nonsteroidal anti-inflammatories, warfarin, antiemetics, and antipsychotics still account for the largest proportion of reports in survey literature. Many of these interactions are pharmacodynamic. Recently, prolongation of the QT interval has become a pharmacodynamic effect of increasing concern with antidepressants, methadone, and many of the newer oral oncology agents.