Evidence on clinically manifest DDIs in older outpatients is scanty. The present study aims to report clinically manifest DDIs, their risk factors, and preventive measures. Older adults with Parkinsonism, infection, coronary artery disease, neuropsychiatric disease, and diabetes mellitus, respectively, had 3.28, 2.85, 1.97, 1.76, and 1.80 times higher odds of DDIs. Those receiving 10 drugs had 5.31 times higher odds of DDIs compared to individuals receiving 1-4 drugs. In conclusion, every fifth case of ADRs and nearly one third of ADR-related hospitalizations in older adults are related to DDIs. A holistic approach with drug omission, optimal patient monitoring, and slow titration of therapy can prevent significant DDIs in older adults.
