How Long Does Demerol Stay in Your System?
Demerol (meperidine) is a narcotic that can be found using many drug screening tests. This may cause some people to wonder, "How long does it stay in your system?" Demerol has an elimination half life of 2.5 to 4 hours, which means the medication will be mostly out of your system in 10 to 20 hours (for most practical purposes but not drug-testing purposes).
Demerol and Drug Testing
Demerol® (meperidine hydrochloride) is a prescription opioid pain reliever. It is a narcotic and is classified as a controlled substance in the United States. Like other narcotics, Demerol can be abused.
Demerol can be found using many (but not all) drug screening tests. As a result, many people wonder how long Demerol will stay in your system.
Half Life of Demerol
The elimination half life of a medication is the time it takes for the blood levels of the medication to be reduced by half. The elimination half life of Demerol in healthy adults is approximately 2.5 to 4 hours. This means that every 2.5 to 4 hours, the level of Demerol in your blood will drop by 50 percent of the previous level.
With an elimination half life of 2.5 to 4 hours, Demerol will be mostly out of your system in 10 to 20 hours (at least for most practical purposes, but not for drug-testing purposes).
This should not be interpreted to mean that a drug test will not "pick up" Demerol after 10 to 20 hours. First of all, some drug tests can check for normeperidine, a metabolite of Demerol that stays in the body much longer (the half life of normeperidine is 15 to 30 hours).
Second, it is difficult to know exactly what blood level of Demerol (or the metabolite) will cause a positive result, since there are many different types of drug tests available. Also, there may be significant differences in Demerol's half life from one person to the next; medical conditions like liver disease may significantly prolong the half life of the drug.