Fentanyl stays in your system for 15–135 hours, depending on the drug’s formulation and various individual factors. Knowing the answer to “How long does fentanyl stay in your system?” is relevant for everyone taking this drug, not only those who have an upcoming drug screening. It can help you minimize the risk of opioid overdose, adverse drug interactions, and more.
This article will cover the key things you should know about fentanyl’s elimination, including the main factors that affect it.
What Is Fentanyl?
Fentanyl is a synthetic opioid prescribed to alleviate severe pain resistant to non-opioid medications. It can also be used as an anesthetic. Fentanyl is about 50 times more potent than morphine and up to 100 times more potent than heroin, which makes it the most powerful—and the most dangerous—opioid medication.
Fentanyl, which is sold both as a generic or brand-name drug, comes in various forms, including:
- Nasal sprays (Lazanda®)
- Buccal tablets (Fentora®)
- Sublingual tablets (Abstral®)
- Sublingual sprays (Subsys®)
- Injectable solution (Sublimaze®)
- Transdermal patches (Duragesic®)
- Transmucosal lozenges (Actiq®)
Fentanyl has a very high potential for opioid abuse, dependence, and addiction. As a Schedule II controlled substance, it can only be legally obtained by prescription and should be strictly used for medical purposes as prescribed by a healthcare professional.
Nonetheless, fentanyl has made its way to the streets in recent years, becoming one of the most popular and deadly illicit drugs in the United States. On the streets, it is known as TNT, Jackpot, Apache, and Dance Fever, among other names. Fentanyl is also frequently used to lace drugs, including sedatives, cocaine, and other opioids, which makes it especially dangerous since the users are not aware of its presence.
In 2022, roughly 83,000 Americans lost their lives to an opioid overdose—a staggering 90% of them—more than 75,000—involved synthetic opioids, primarily fentanyl.
How Does Fentanyl Affect Your Body?
Fentanyl affects the body by binding to opioid receptors and inhibiting the transmission of pain signals between the body and the brain. It has a very rapid onset of action—just 5–15 minutes—and produces pain relief for up to four hours, though some formulations may take longer.
Moreover, fentanyl triggers a sudden release of dopamine, inducing euphoria and deep relaxation. Unfortunately, this may encourage people to abuse the drug, increasing the risk of prescription drug addiction and overdose.
Fentanyl can also cause various side effects, some of which may require immediate medical attention or have long-term consequences, such as organ injury and fertility problems.
The most common fentanyl side effects are:
- Itchy skin
- Confusion
- Headache
- Drowsiness
- Constipation
- Stomach ache
- Lightheadedness
- Reduced appetite
- Difficulty breathing
- Nausea and vomiting
Fentanyl Half-Life
Fentanyl’s half-life ranges between 3 and 27 hours, depending on the drug’s formulation.
Fentanyl’s elimination half-life indicates how much time it takes for the body to reduce the concentration of the drug by 50%. If you’re using fentanyl lozenges, for example, your body might need as little as 3 hours to remove half a dose, whereas transdermal patch users may require upwards of 25 hours.
Now, let’s discuss the question, “How long does fentanyl stay in your system?” in greater detail.
How Long Does Fentanyl Stay in Your System?
The answer to “How long does fentanyl stay in your system?” varies based on the drug’s formulation. Since it takes around five half-lives to eliminate the drug, fentanyl can stay in your system anywhere between 15 and 135 hours. Nonetheless, various drug tests may be able to detect it far beyond this timeframe.
Let’s explore the fentanyl detection window for blood, hair, saliva, and urine tests.
How Long Does Fentanyl Stay in Blood?
Fentanyl stays and remains detectable in blood for around 12 hours following administration, though some tests may detect its metabolites for up to 48 hours and more. Blood testing for fentanyl is not that common due to its invasive nature and short detection window.
How Long Does Fentanyl Stay in Hair?
Fentanyl can be detected in hair samples for up to 90 days after the last dose. Hair follicle tests have the longest detection window for fentanyl but tend to be quite expensive. They are typically used to test for long-term fentanyl use and abuse.
How Long Does Fentanyl Stay in Saliva?
Saliva tests are the least reliable method of fentanyl testing. A study by Silverstein et al. found that neither fentanyl nor its metabolites could be detected in saliva. Therefore, saliva testing is not recommended for fentanyl detection.
How Long Does Fentanyl Stay in Urine?
Fentanyl stays in urine for up to 72 hours after the last dose. Some tests can detect its metabolites in urine samples for up to four days. Urine tests are often conducted to detect fentanyl since they are relatively affordable, easy to administer, and reliable.
When considering the question “How long does fentanyl stay in your system?” keep in mind that the answer also depends on various individual factors besides the drug’s formulation. Let’s see what they are.
Factors That Determine How Long Fentanyl Stays in Your System
One of the main factors that determine how long fentanyl stays in your system is liver function, as fentanyl is predominantly metabolized in the liver. Kidney function also plays an important role, as around 10% of fentanyl and its metabolites are excreted by the kidneys. Therefore, if you suffer from renal or hepatic problems, your body will need more time to eliminate fentanyl.
The answer to the question “How long does fentanyl stay in your system?” may also vary individually based on the following factors:
- Metabolic rate. The faster your metabolism is, the less time you will need to clear out fentanyl. Factors that impact your metabolism—age, weight, body composition, and even diet—may also affect how long fentanyl stays in your system.
- Extent of fentanyl use. How long fentanyl stays in your system also depends on the frequency, amount, and duration of your fentanyl use. The longer you’ve been taking fentanyl, the more time it will take for your body to process and eliminate it. Similarly, those who take fentanyl in higher doses may need more time to metabolize it.
- Use of other substances. Some substances, including alcohol, prescription medications, and supplements, may interact with fentanyl. This can affect how quickly your body breaks down substances and, consequently, how long fentanyl stays in your system. For your safety, do not take opioids with other substances without your doctor’s approval.
Fentanyl Addiction vs. Fentanyl Dependence
Fentanyl addiction and fentanyl dependence are distinct yet often co-occurring conditions that anyone taking this drug can develop—including those who take it as prescribed.
Prolonged fentanyl use makes you particularly vulnerable to opioid dependence and opioid addiction, also known as opioid use disorder (OUD). If you take fentanyl for an extended time, you will inevitably develop tolerance to it, which means your usual dose will no longer produce the same effects as before.
Tolerance is a sign of physical dependence on fentanyl. If you develop opioid tolerance, the worst thing you can do is to increase your fentanyl dosage without consulting your doctor. Not only does this constitute opioid abuse, but it also increases the risk of opioid toxicity and overdose.
Furthermore, people dependent on fentanyl experience opioid withdrawal symptoms upon drug discontinuation. Since these symptoms are rather distressing, it’s not uncommon for people to keep taking fentanyl just to prevent them. However, getting professional help for opioid dependence is vital; otherwise, it can escalate into an opioid addiction.
Unlike fentanyl dependence, fentanyl addiction is mainly psychological. Those addicted to this drug continue to use it, even if it takes a toll on their work performance, relationships, and so forth. Luckily, fentanyl addiction can be treated, regardless of how long you’ve been battling it.
Fentanyl Withdrawal Symptoms
Fentanyl withdrawal symptoms are a set of physical and psychological symptoms that occur when people attempt to quit fentanyl after becoming dependent.
People who use fentanyl regularly may begin to experience the initial withdrawal symptoms within the first 12 hours following the last dose. These symptoms usually subside within a couple of weeks after discontinuation, though psychological symptoms may linger longer. Some people continue to suffer from them for several weeks and even years.
The most common fentanyl withdrawal symptoms include:
- Chills
- Anxiety
- Nausea
- Diarrhea
- Vomiting
- Irritability
- Insomnia
- Depression
- Mood swings
- Loss of appetite
- Fentanyl cravings
- Increased sweating
- Muscle and joint aches
- Elevated blood pressure and body temperature
- Flu-like symptoms (runny nose, fever, watery eyes, etc.)
Going through fentanyl withdrawal significantly increases the risk of fentanyl overdose. Sadly, it’s not uncommon for people to relapse in hopes of relieving pain. However, since abstinence reduces tolerance, this is extremely dangerous; if you relapse, even your usual dose can cause an opioid overdose. If not treated promptly, it can be deadly.
Quitting fentanyl “cold turkey” also isn’t recommended due to an increased risk of severe symptoms, relapse, overdose, and death. For this reason, your best option is to seek professional opioid addiction treatment.
ANR Opioid Dependence Treatment
Accelerated Neuro-Regulation (ANR) is an ultra-modern, safe, and effective treatment for opioid dependence that has helped nearly 25,000 people worldwide return to an opioid-free life.
ANR differs from other opioid treatment programs in that it treats the root of opioid dependence as opposed to its symptoms. It is the first and only treatment that acknowledges and tackles the neurochemical causes of opioid dependence by re-regulating the endorphin-receptor system. Since this negates the risk of relapse, ANR has an exceptionally high success rate.
Effectiveness is not the only advantage of ANR. This treatment is also time-efficient; our patients spend only 36 hours on average hospitalized, which means ANR can help you beat opioid dependence within a matter of days.
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Key Takeaways
Since many different factors affect the body’s ability to metabolize and eliminate opioids, the answer to “How long does fentanyl stay in your system?” varies from one person to the next. Nonetheless, we hope this article helped you learn more about fentanyl elimination.
Before you leave, let’s summarize the key points we covered:
- Fentanyl is an extremely potent synthetic opioid medication used to manage severe pain that cannot be treated with weaker painkillers.
- Fentanyl’s half-life ranges from 3 to 27 hours, meaning it may take up to 135 hours for your body to remove it.
- How long fentanyl stays in your body depends on the type of fentanyl you take, your metabolic rate, liver and kidney function, the extent of your opioid use, and whether or not you’re taking any other substances alongside fentanyl.
How Long Does Fentanyl Stay in Your System FAQ
It can take between 15 and 135 hours to get fentanyl out of your system, as it largely depends on the drug’s formulation. Some other factors that may affect how long fentanyl stays in your system include liver and kidney function, the extent of your fentanyl use, and your metabolism.
Fentanyl is primarily eliminated from the body through urine after being metabolized in the liver into norfentanyl and other metabolites. Around 10% of it is also metabolized in the kidneys.
You will begin to feel pain relief shortly after taking fentanyl. Besides that, fentanyl can also make you feel drowsy, relaxed, and euphoric. However, you should never take it for other purposes or in ways other than prescribed. If you experience any side effects, such as itching, confusion, or constipation, after taking fentanyl, contact your doctor.
Fentanyl effects usually last for up to four hours. However, the duration of action may vary based on the type of fentanyl you take, the dosage administered, and other individual factors.
Fentanyl is very addictive, even when taken as prescribed. Repeated exposure to this powerful prescription opioid alters brain chemistry, which is why you should ideally take it for minimum time and in the smallest doses possible. To reduce the risk of fentanyl addiction, carefully follow your doctor’s instructions.
Additional Information:
Mixing Fentanyl and Alcohol: The Lethal Combination Explained
Fentanyl vs. Percocet: Differences, Effects & Addiction Risks
Rapid Fentanyl Detox: Risks, Considerations & Alternatives
