Impact of Drug-to-Drug Interactions on Patients With Advanced Cancer in Palliative Care Settings

BACKGROUND: Drug-to-drug interactions (DDIs) pose a significant challenge in managing elderly patients with chronic illnesses and polypharmacy. Similarly, patients with advanced malignancies often experience complex symptoms that necessitate the use of medications such as narcotics, tranquilizers, laxatives, antiemetics, and antipsychotics, drug classes known for their high risk of severe and potentially fatal interactions. AIM: The aim of this study is to assess the prevalence of DDIs, their categories and clinically significant adverse events among palliative care patients in Armed Forces Hospital, Southern Region, Saudi Arabia. METHODS: We conducted a prospective cross-sectional study involving palliative patients with advanced malignancies at the Palliative Medicine Department of Armed Forces Hospital, Southern Region, Saudi Arabia. The study evaluated the number of prescribed medications, the occurrence and categories of DDIs, their clinical significance, and the strategies used for management. RESULTS: We enrolled 40 patients with advanced malignancies, with a mean age of 74 years (±14.5), ranging from 27 to 93 years, and nearly equal distribution of male patients (52.5%) and female patients (47.5%). DDIs were reported in 75% of the patients, with the majority (66.1%) classified as moderate in severity. Only 17.5% of patients experienced adverse effects related to DDIs, with sedation and confusion being the most frequently reported. Patients with DDIs also tended to have more severe symptoms, particularly pain, depression, and appetite loss. Polypharmacy, with a mean of 10.3 medications per patient, emerged as a key factor contributing to DDIs. Conclusion: DDIs are relatively common among palliative care patients, but clinically significant adverse events are infrequent. Given the small sample size and single-center design, findings should be interpreted with caution. Regular medication reviews and tailored prescribing may support safer, more patient-centered care at the end of life.