Older adults are generally more sensitive to trazodone's sedating and blood-pressure-lowering effects, which raises the risk of falls, dizziness, and confusion. Many prescribers start with a notably lower dose in this age group and increase more slowly than they would for a younger adult.
This increased sensitivity doesn't mean trazodone is off-limits for older adults — it's actually used fairly often in this population, sometimes specifically because it's not a controlled substance and has a different risk profile than some benzodiazepine alternatives. It does mean dosing and monitoring should reflect this added caution.