How Long Does Fentanyl Stay in Your System?

Fentanyl is a synthetic opioid analgesic. Brand names for oral applications of fentanyl include Abstral, Actiq, Fentora, and Onsolis, which are lozenges, films, and tablets. Fentanyl transdermal patches include brand names Duragesic and Ionsys. Fentanyl is a Schedule II controlled substance in the United States, meaning that it has accepted medical use and a high potential for addiction.

Fentanyl is 50 to 100 times more potent than morphine. If you aren't sure how much you are taking, it can be very easy to overdose. The average lethal dose of fentanyl is only 2mg. New fentanyl analogs that are more potent than fentanyl have also been found in use. While fentanyl is not tested for on standard drug tests, it is tested for by specific employers.

In 2017, 28,400 people died from overdoses involving synthetic opioids other than methadone, according to the CDC. The CDC goes on to cite the National Center for Health Statistics, stating that 29% of all drug overdose deaths in 2016 mentioned fentanyl, a 1045% increase from 2012.

Fentanyl is prescribed to opioid-tolerant pain patients as a lozenge or in the form of a transdermal patch, sometimes sold under the brand name Duragesic.

The effects of fentanyl may include:

• Relief from pain
• Euphoria
• Nausea
• Reduced sex drive
• Shallow breathing

The lozenge takes effect within a few hours. With the patch, it can take anywhere from a few hours to a full day to start feeling the effects. Do not apply extra patches if you feel it is not effective right away.

A 100 microgram patch delivers 100 micrograms of fentanyl per hour, containing 168 hours worth of fentanyl.

Fentanyl is mainly broken down in the liver into norfentanyl, with some of both substances broken down by the kidneys. According to one study, norfentanyl can be detected for up to four days after last use.

Fentanyl can be detected using urine, hair, and blood tests. Drug tests commonly used to detect fentanyl typically employ mass spectrometry, which is also used to test the contents of drug samples by drug checking services.

Fentanyl can show up on a blood test between five and 48 hours after the last use.

You can test positive for fentanyl on a urine test between one and three days after the last time you used it. This is the most common test used by an employer.

Hair tests are less commonly used by employers but can detect fentanyl for up to three months after the last use.

The presence of Benadryl (diphenhydramine) can trigger a false positive for fentanyl. Let your testing agency know if you have recently taken Benadryl if they are going to be testing you for opiates.

If you have been prescribed fentanyl and have to take a urine drug screen, it is also wise to disclose this to the testing lab. 

While none of these factors substantially impact how long a person has to stop using before a drug test in order to test negative, how long fentanyl is present in the body depends on several factors.

The more fentanyl in the body, the longer it will take to fully be eliminated from the body.

Impaired renal or liver function will lead to slower metabolism of fentanyl.

Patients taking fentanyl to help manage pain for severe burns may experience faster clearance of the drug than others as a result of increased cardiac output and hepatic blood flow, according to a 2017 study.

Differences in thickness of the skin and subcutaneous fat in various places on the body mean that the rate of absorption of fentanyl is different depending on where the patch is placed. A patch applied to the legs will absorb less efficiently than on the arms, which means the elimination of the drug will also be slower.

Drinking lots of water, exercising, and other elimination myths will not help you get fentanyl or other opiates out of your system to beat a drug test. The only way to get fentanyl out of your system is to stop taking the drug and allow your body time to metabolize and eliminate it.

If you want to get fentanyl out of your system because you feel you have taken too much and you do not want to be at risk for a respiratory arrest, seek medical attention immediately. While naloxone will not actually remove fentanyl from your system, administering it will block the opiate receptors in the body, causing you to go into withdrawal. This is unpleasant but definitely preferable to an overdose.

Fentanyl can have dangerous cross-reactions with Xanax, Klonopin, Ativan, and alcohol, which amplify the depressing effects on the central nervous system. The following are symptoms of an overdose from an opiate such as fentanyl:

• Fingernails and lips turn blue or purplish black
• Pulse (heartbeat) is slow, erratic, or not there at all
• Non-responsive to outside stimulus
• Awake, without the ability to speak
• Loss of consciousness
• Very slow, shallow, erratic, or stopped breathing
• The skin of darker-skinned people looks grayish or ashen and the skin tone of lighter-skinned people looks bluish purple
• Vomiting
• Making a snore-like gurgling noise or "death rattle," choking sounds
• Body is limp
• Face is pale or clammy

An overdose emergency should be treated immediately with naloxone. Naloxone is available in many pharmacies and from your local health department. If many people in your area are using opiates or drugs purchased illegally that may have been mixed with fentanyl, it is a good idea to carry naloxone. You could save a life.

Fentanyl is so potent it is highly recommended to not deviate from your prescribed dose, as even a slightly greater amount can dramatically amplify the effects and increase the risk of overdose.

Fentanyl carries a high risk of dependence, even when taken as prescribed. If you suddenly stop taking fentanyl, you may experience opioid withdrawal symptoms, such as anxiety, muscle aches and pain, excessive sweating, and insomnia. Withdrawal can begin six to 30 hours after your last dose and last for up to 10 days.

If want to stop taking fentanyl, consult your doctor. When transitioning off of opioids like fentanyl, your doctor may prescribe other medications to ease withdrawal symptoms and prevent breakthrough pain. Opioid addiction may also be treated with other drugs that help shorten and alleviate symptoms of withdrawal.

Treatment options for opiate use disorder include:

• Medication-assisted treatment (MAT) with buprenorphine or methadone
• Harm reduction psychotherapy
• Programs designed to help get you off of opiates in a sustainable way

If you have chronic pain and are worried about stopping the medication, your health provider can work with you to get access to pain-relief that is less of a problem for your substance use disorder.

If you are not in a position to stop using or to get into a treatment program, make sure to employ harm reduction methods:

• Don't take more than your prescribed dose.
• Pursue a safe supply. Always use a prescription rather than purchasing a substance of unknown purity.
• Seek out a safe space to use where you can be supervised by a professional.
• Let a loved one who carries and knows how to use naloxone know that you are going to be using.

Dependence on fentanyl or other opiates is not a cause for shame. Tell someone you trust and seek support.