The pain-relieving effects of Demerol are only felt for a few hours. The metabolites of the drug stay in the body for longer than the active ingredient.
Demerol does not show up on a standard five-panel drug test. There are specialized drug tests that can detect their metabolites.
What is Demerol?
Demerol is the brand name for the narcotic analgesic meperidine. It is a pain reliever that is prescribed to treat moderate to severe pain over a short period of time.
Demerol is usually associated with dental procedures, medical surgeries, and obstetrical care. The drug interacts quickly with the brain in order to decrease pain within approximately 15 minutes.
Medical professionals recommend that this drug not be taken for more than two days or in higher doses for a period of time beyond what was prescribed.
If a dose is missed, it is highly discouraged to take a double dose to make up for going off schedule. The patient should contact their doctor for advice on the appropriate course of action considering their unique medical situation.
What is Half-Life?
Medication prescriptions include dosage amounts that take into consideration the half-life of a drug for effective and safe consumption.
The half-life of medication simply refers to how long it takes for half of the dosage to be metabolized and eliminated from the bloodstream, or diminished by half.
For treatment to be successful, it is important to consistently take the prescribed medication on a continuous plan until otherwise advised by your doctor. The same is true when it comes to increasing or decreasing dosages or stopping treatment altogether. It should only be done under the directive of a doctor.
The goal is to achieve a steady balance of the amount of medication going in and the amount of medication a patient is eliminating from their system.
How is Demerol Metabolized?
Demerol is primarily metabolized by hydrolysis in the liver and converted to an active metabolite called normeperidine. Roughly 30 percent of Demerol is eliminated in urine.
Regardless of what the half-life of a medication is, it takes four times that duration for the absorption of the drug to level off and reach a constant status in the body.
Withdrawal occurs when the blood level of the drug is not in homeostasis or is not stable. This is why it is important for a patient to follow their doctor’s plan to decrease the dosage of Demerol rather than suddenly stopping intake all at once. The result of abruptly stopping treatment may cause the body to react in a toxic way, producing withdrawal symptoms that can be incredibly uncomfortable.
Bioavailability and First-Pass Metabolism
The oral bioavailability of Demerol is 50 to 60 percent in a patient with a healthy liver due to first-pass metabolism. In first-pass metabolism, the liver acts as a filter to metabolize the drug before it reaches the rest of the body.
The half-life of a drug is not the same from person to person. Each patient’s body will metabolize Demerol differently depending on a number of factors.
Some of the factors may include:
- Age: The older the person, the slower the elimination period.
- Health: Complications or diseases will slow elimination processes.
- The frequency of use: Higher rates of use can create a buildup in the system, slowing elimination.
- Additive substances: Taking meperidine while consuming alcohol or other substances will cause elimination to take longer.
- Metabolism: A faster metabolism will cause the drug to leave the system faster.
- Hydration: A well-hydrated person will eliminate the drug faster.
If Demerol is not taken orally and is injected intravenously, the drug will bypass the small intestine and liver. It will not be filtered, resulting in 100 percent bioavailability.
A considerable risk that comes with taking Demerol is the elimination process. Meperidine is metabolized into normeperidine, which is potentially dangerous to the nervous system and can act as a poison, damaging nerve tissue.
Different drug tests detect Demerol or its metabolites for varying amounts of time.
Demerol metabolites have different half-lives.
- Meperidine: 2 to 5 hours
- Meperidine in those with liver damage or disease: 7 to 11 hours
- Normeperidine: 15 to 30 hours
- Normeperidine in those with renal impairment: 35 to 40 hours
Demerol does not usually show up on standard urine drug tests.
Since it is a synthetic opioid, the body does not metabolize it to morphine, which is what normally shows up on urine drug tests.
There are specialized urine tests that can detect the presence of the metabolites of synthetic opioids.
Hair follicle tests will show the presence of drugs for up to 90 days after use.
Caution for the Elderly
For patients over 65 years of age, AARP encourages extreme caution when using Demerol. Since Demerol is an opioid analgesic medication, it is known to enhance confusion, falls, seizures, and hallucinations in adults of advanced age.
The best practice is to only take your medication as prescribed. If you must take a drug test, inform the entity administering it that you have a legitimate prescription and take your medication according to that prescription. You will likely have to provide proof of that prescription.