Assessment of drug–drug interactions between chemotherapeutic and chronically used medications at Khartoum Oncology Hospital

Background: Drug–drug interactions (DDIs) in oncology are significantly crucial because chemotherapeutic drugs usually have a narrow therapeutic index. Many DDIs are expected to be present between chemotherapeutic agents and chronically used medications as the number of DDIs increases in parallel with the number of drugs taken. Because of the limited literature about this area in Sudan. Thus, this study was conducted to assess the DDIs between chemotherapeutic and chronically used medications in Sudanese patients.Methods: This study was carried out in Khartoum Oncology Hospital from March to May 2019. The data were collected using data collection sheets that were filled from patient records and direct interviews with the patients. The presence of DDIs was detected by Lexicomp® drug interaction software. Results: A total of 117 patients have been involved in this study. The main DDIs between chemotherapeutic and chronically used medications were identified in 20.5% of patients, which represented 8% of the total DDIs between all drugs. Of these, 76% of the DDIs were pharmacodynamic (PD), 20% were pharmacokinetic (PK), and 4% were both PD and PK. The majority (92%) of these DDIs have been moderate in severity and had the risk rate of C (84%). 12.5% of these patients experienced clinical consequences for which they were admitted to the emergency department. DDIs between antihypertensive medications and paclitaxel were the most common (68%). There was a significant association between the age and the presence of DDIs (P = 0.017). Conclusion: DDIs between chemotherapeutic and chronically used medications represented 8% of the total identified DDIs in the study patients.