This population-based cohort study aims to evaluate the safety of initiating a new outpatient prescription of citalopram at 20 mg/day (higher dose) compared to 10 mg/day (lower dose) in adults aged 65 years and older with reduced kidney function. The primary research question is whether initiating a higher dose of citalopram (20 mg/day) versus a lower dose (10 mg/day) in older adults with low kidney function (defined as an estimated glomerular filtration rate \[eGFR\] less than 45 mL/min per 1.73 m2, without dialysis or a history of kidney transplantation) is associated with an increased 30-day risk of a composite outcome comprising all-cause hospitalization, all-cause emergency department visits, or all-cause mortality.