Trazodone's duration and how long it lasts in the body depend on the formulation and individual factors.

• Immediate-release trazodone typically lasts about 4 to 6 hours, making it suitable for helping initiate sleep. Extended-release formulations last longer, around 8 to 12 hours, providing sustained effects useful for managing depression or maintaining sleep throughout the night

• The half-life of trazodone, which is the time it takes for the blood concentration to reduce by half, generally ranges from about 5 to 13 hours, commonly around 10 hours. This means it can take roughly 1 to 2 days (25 to 45 hours) for trazodone to be fully eliminated from the body after the last dose

• Although trazodone stays in the system for up to 1 to 3 days, its therapeutic effects, especially the sedative effects for sleep, usually last only several hours (around 5 to 9 hours)

• Factors such as age, metabolism, liver and kidney function, dosage, and frequency of use can influence how long trazodone lasts and how quickly it is cleared from the body

In summary, trazodone's sedative effects generally last 4 to 12 hours depending on the formulation, while the drug itself remains in the body for 1 to 3 days before being fully cleared.