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. As little as 2 mg of fentanyl can be lethal. 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.

How Long Does It Take to Feel Effects?

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 acute effects of fentanyl may include:

• Dizziness
• Drowsiness
• Euphoria
• Nausea
• Relief from pain

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

How Long Does Fentanyl Last?

Fentanyl patches range from 12 to 100 micrograms an hour and are generally changed every 72 hours. Fentanyl is mainly broken down in the liver into norfentanyl and mostly excreted 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 chromatographic and mass spectrometry techniques.

Blood

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

Urine

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

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

False Positive Testing

The presence of Benadryl (diphenhydramine) and some other medications can possibly trigger a false positive for fentanyl. Let your testing agency know if you have recently taken Benadryl or any other medications 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. 

Factors That Affect Detection Time

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.

• Dose: The more fentanyl in the body, the longer it will take to fully be eliminated from the body.
• Metabolism: Impaired renal or liver function will lead to slower metabolism of fentanyl.
• Location of the patch: 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.

How to Get Fentanyl Out of Your System

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.

While Narcan (naloxone), a nasal spray used to treat opioid overdose in an emergency situation, 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.

Symptoms of Overdose

Fentanyl can have dangerous cross-reactions with other sedatives such as Xanax (alprazolam), Klonopin (clonazepam), Ativan (lorazepam), 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:

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

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.

Getting Help

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.

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:

• Take only your prescribed dose
• Pursue a safe supply
• Use a prescription rather than purchasing a substance of unknown purity
• Seek out a safe space to use where you can be supervised
• Let a loved one who carries and knows how to use naloxone know that you're using