Prescription drugs, even though they may last a matter of hours, can last days in the human body. The amount of time a certain medication stays in your system is dependent upon the drug itself as well as how long you have been taking it and your individual physiological makeup.
HomeDrugTestingKit.com reports that benzodiazepines, sedatives including such drugs as Ativan and Xanax, can remain in the system for up to 10 days.
The opioid family of medication, including such drugs as Percocet and Vicodin, can also last up to 10 days in the body.
Anti-depressants also last up to 10 days in the body, especially if you have been taking them regularly for longer than a month.
The stimulant family of medications, drugs used to treat ADD/ADHD, such as Ritalin, last two to four days in the body.
The oldest form of sedatives, such as phenobarbital, last between two to four days in the body.
Your body weight and the length of time you have been taking the drug will affect the amount of time it stays in your system.