How Long Does Fentanyl Stay in Your System?
Fentanyl is a powerful opioid medication that is often prescribed for severe pain. An increasing amount of street drugs are secretly cut with fentanyl, and people who struggle with illicit drug use may therefore be unintentionally exposed. If you or a loved one is taking fentanyl or drugs that may be cut with fentanyl, it’s important to understand how long fentanyl stays in the body.
Duration of Effects of Fentanyl
Because fentanyl is available in many different dosage forms, its effects can last for varying amounts of time. Methods of use for fentanyl include:
- Injection: Starts to work in less than 2 minutes
- Oral lozenge: Reaches its peak level in blood anywhere from 20 minutes to 8 hours after use, depending on the dose
- Skin patch: Lasts for a total of 72 hours, releasing the drug at a fairly constant rate for the duration
- Nasal spray: Reaches its peak level in blood about 15 to 21 minutes after use
- Oral disintegrating tablet: Reaches its max level in blood anywhere from 15 minutes to 4 hours after use
- Oral buccal tablet: Reaches its peak level in the blood anywhere from 20 minutes to 4 hours after being taken
The half-life of a drug is how long it takes for half of it to leave your system. The half-life of fentanyl depends on the dosage form being used. In some cases, the half-life also depends on the dose being used. Half-lives for dosage forms are as follows:
- Injection: Half-life is around 3.5 hours
- Oral lozenge: Half-life ranges from 3.5 to 6.5 hours
- Skin patch: Half-life ranges from 3 to 12 hours
- Nasal spray: Half-life ranges from 15 to 25 hours, depending on the dose
- Oral disintegrating tablet: Half-life is anywhere from 5 to 13.5 hours, depending on the dose
- Oral buccal tablet: Half-life ranges from 2.5 to 11.5 hours in blood, depending on the dose
How Long will Fentanyl Show in Drug Tests?
Fentanyl can show up in drug tests for different amounts of time, depending on what is being tested.
Although fentanyl leaves the body mainly in the urine, it does not always show up in standard urine tests. Special urine tests that specifically screen for fentanyl may be needed. When a fentanyl-sensitive test is used, the drug may show up immediately in the urine and be detectable for about 72 hours. However, at least one of fentanyl’s byproducts may show up in urine for at least 96 hours.
Fentanyl can show up in the blood for around 48 hours after use. With lower doses, the drug may clear the blood more quickly.
In the past, fentanyl often did not show up in saliva tests. Over the past several years, however, technology has improved and new techniques have been developed for finding fentanyl in saliva. Currently, it is not yet clear how long fentanyl lasts in the saliva with some of these new techniques.
Fentanyl can show up in hair for months. One study showed that hair tests could find fentanyl in people who had used the drug over the previous year. In general, hair testing has an extended detection window of 1 month per half-inch of hair.
Factors Affecting How Long Fentanyl Stays in Your System
Several factors impact how long fentanyl stays in your system, including:
- Amount used: If you use a higher dose of fentanyl, it may take your liver longer to break down the drug
- Frequency of use: Fentanyl may build up in the body of someone who regularly uses it, meaning that it will take longer to leave the system
- Method of use: Depending on the route of administration, fentanyl can last for different durations. For example, injected fentanyl leaves your body more quickly than fentanyl from a nasal spray
- Age: Because older people may be more sensitive to fentanyl and may require much lower doses, they may be able to clear the drug more quickly than a younger person on a much higher dose
- Overall health: Someone with a healthy liver and healthy kidneys may clear the drug more quickly than someone in poor health
False Positives for Fentanyl
Because fentanyl is a synthetic opioid, it is not chemically related to substances that can cause false positives for other opioids. Therefore, false positives for fentanyl are rare. However, some data suggests that the antidepressant trazodone may cause a false positive for fentanyl. If you use trazodone and are being drug tested, inform the person who is administering the test.
How Fentanyl Is Broken Down in the Body
After fentanyl gets into your bloodstream, it goes to the liver to be broken down. The main byproduct of fentanyl is the inactive product norfentanyl. Both fentanyl and its byproducts leave the body mainly in the urine. To a smaller extent, they also leave the body in the feces.
How to Flush Fentanyl Out of Your System
Because fentanyl needs to be processed by the liver before it can be removed from the body, there is no way to speed up the process. The liver uses an enzyme called CYP3A4 to break down the drug. A finite amount of this enzyme exists in the liver, and there is no way to make more to speed up fentanyl processing.
Key Points: How Long Does Fentanyl Stay in Your System?
Key points about how long fentanyl stays in your system include:
- Fentanyl is available in many different dosage forms that can last varying amounts of time
- Fentanyl can last for days in most bodily fluids
- Technology for finding fentanyl in saliva is new, so it is not yet clear how long fentanyl stays in this fluid
- Because the liver needs to process fentanyl before it leaves your body, there is no quick way to flush fentanyl from your system
If you or a loved one struggle with fentanyl or other opioids, The Recovery Village Ridgefield is here to help. Contact us today to learn more about treatment options that can suit your situation.
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