Toxicity profile, adverse drug reactions and drug-drug interactions among geriatric cancer patients under metronomic chemotherapy in a South Indian tertiary care hospital

Objective The study aims to examine the toxicity profile, pattern of adverse drug reactions (ADRs) and drug-drug interactions (DDIs) in geriatric cancer patients receiving metronomic chemotherapy. Patients and Methods Patients were followed after each cycle till 12 weeks. Haematological parameters such as complete blood count, liver function test and renal function test were recorded from the baseline to the final visit. The Common Terminology Criteria for Adverse Events (CTCAE) scale was used to characterise the toxicity profile. ADRs that the patients had were documented and assessed for its causality, severity and preventability. The Lexicomp drug interaction checker was used to grade DDIs. Results Of 129 patients, according to CTCAE grading, haemoglobin indicated grade 1 toxicity, while other haematological parameters revealed no toxicity. Although there was a statistically significant difference in ALT, alkaline phosphate, serum creatinine and potassium ( p < 0.05), it was not clinically significant. A total of 226 ADRs were documented. Anaemia was the most frequently occurred ADR (14%) and Capecitabine caused the highest number of ADRs. Assessments of causality showed that the majority of cases are “possible” (63%). In evaluating the severity of ADRs, 99% ADRs were “mild” and 61% of ADRs were “probably” preventable. Upon assessing the DDIs, 82% of the prescriptions had “no known interaction”. Conclusion Metronomic chemotherapy in geriatric cancer patients exhibited grade 1 toxicity for haemoglobin. Anemia was the most common ADRs. The majority of cases were “possible” in causality, “mild” in severity, and “probably” preventable. The majority of the prescriptions have no known DDIs.