Prednisone typically stays in your system for about 16 to 22 hours after the last dose. This is based on its elimination half-life of approximately 3 to 4 hours, meaning it takes about five half-lives (15 to 20 hours) for the drug to be mostly cleared from the bloodstream
. However, the total time prednisone and its metabolites remain detectable varies by the type of test and individual factors:
- Blood: Prednisone is usually cleared within 16 to 22 hours
- Urine: Prednisone and its metabolites can be detected for up to 24 to 36 hours, sometimes longer depending on dosage and kidney function
- Saliva: Detectable for about 12 to 24 hours after ingestion
- Hair follicles: Prednisone metabolites can be found for up to 90 days due to accumulation in hair shafts, though hair testing is rarely used for this drug
Several factors influence how long prednisone stays in your system, including dosage, frequency of use, metabolic rate, age, body mass, liver and kidney function, and interactions with other medications
. In summary, while prednisone is generally eliminated from the blood within about a day, its metabolites may persist longer in urine and hair, and individual factors can extend these timeframes.
