Prevalence, severity, and nature of risk factors associated with drug-drug interactions in geriatric patients receiving cancer chemotherapy: A prospective study in a tertiary care teaching hospital.

INTRODUCTION

Polypharmacy increases hazard of drug-drug interactions(DDIs), hospitalization, treatment toxicity, and mortality in elderly individuals with cancer. The present study explores and analyzes prevalence and severity of DDIs in geriatric cancer patients subjected to anticancer chemotherapy, their mechanisms, stratification of severity, and correlation between DDI risk and number of medications taken.

METHODS

This was a cross-sectional study conducted between January-July 2019 at the Medical Oncology/Hematology and Radiation-Oncology Departments, All India Institute of Medical Sciences(AIIMS) Rishikesh. The study included a convenience sampling of 126 geriatric cancer patients.

RESULTS

126 patients were enrolled in present study. DDIs were identified in 97.6% of elderly cancer patients, and 88.9% had at least one DDI with antineoplastic medications. Highest number of DDIs involving antineoplastic medications in any given patient was 12. DDIs involving medications used for treatment of non-cancerous diseases were observed in 83.3% of patients; highest number of interactions identified in any given patient was 15. Out of 473 interactions, 237(50.1%) DDIs were attributable to pharmacodynamic mechanisms of action. 126(27%) of DDIs involved pharmacokinetic mechanisms and 110(23.6%) involved unknown mechanisms. In this present study, total number of DDIs could be positively correlated with total number of medications and number of health problems.

CONCLUSIONS

Geriatric cancer patients are at high risk of DDIs ascribable to polypharmacy. Physicians may utilize online DDI checking softwares to alert themselves, characterize potential DDIs, and modify medications judiciously. An integrative and algorithmic approach with inclusion of geriatricians, oncologists, cardiologists, general practitioners, and clinical pharmacologists/ pharmacists is imperative to optimize drug therapy.