How Long Does Carfentanil Stay In Your System?

The amount of carfentanil in the blood peaks within the first hour and decreases to half after 7.7 hours.

Carfentanil is a potent synthetic opioid that is difficult to detect on standard drug screens. It is a dangerous drug that can be unknowingly ingested because it is often mixed into street drugs like heroin and prescription pills.

If carfentanil is in your system, it can take about 2.5 days for it to be eliminated from your body. Carfentanil and its metabolites may stay in urine for 3-4 days and can be detected in hair follicles for up to 3 months.

Carfentanil is only approved for use in large animals because of its potency. It is an analog of fentanyl, which is a prescription opioid painkiller used to treat chronic pain or severe pain.

Pharmaceutical fentanyl is available as a transdermal patch or lozenges that can be up to 100 times more powerful than morphine.

It is only prescribed if an individual is tolerant to other opioids. Carfentanil, however, is up to 10,000 times stronger than morphine and 100 times stronger than fentanyl.

Effects & Metabolism Of Carfentanil

Carfentanil attaches to opioid receptors in the central nervous system and releases dopamine. It can cause a rush of euphoria and feelings of relaxation. However, it can also cause extreme drowsiness, sedation, and lightheadedness, similar to the side effects of fentanyl.

Fentanyl and its analogs also slow down important bodily functions, like breathing and heart rate. Even a small amount of fentanyl can cause respiratory depression, also known as an opioid overdose. A fentanyl overdose is life-threatening and requires immediate medical care.

The amount of carfentanil in the blood peaks within the first hour and decreases to half after 7.7 hours. This is known as a drug’s half-life and can be used to determine how long a drug will stay in the system.

After about five half-lives, or 38.5 hours, the majority of the drug will be eliminated from the system.

Carfentanil Drug Testing & Detection Times

Several factors can affect how long carfentanil is detected on a drug screen, including your body mass, liver health, frequency of use, and length of drug use.

In addition, a drug creates metabolites when it is processed, which can extend the amount of time the drug is detected. Most opioids are metabolized into morphine, which is the opiate most standardized tests can detect.

However, carfentanil metabolizes into norcarfentanil and fentanyl is processed into norfentanyl. These synthetic opioids require a specific test that detects their unique metabolites.

Urine Tests

Carfentanil can be detected in the urine 2-4 days after last use. However, heavy use can cause its metabolites to be detected for up to 2 weeks.

Blood Tests

A blood test is not commonly used because it is invasive, expensive, and can only detect recent use. A blood test can detect fentanyl use for up to 48 hours.

Saliva Tests

Although most opioids can be detected on saliva tests for up to 48 hours, the National Library of Medicine reported that fentanyl and its metabolites are not detectable in saliva.

Hair Tests

A hair follicle test, which will test up to 1.5 inches of hair, has the longest window of detection. Hair follicles can hold carfentanil metabolites for up to 90 days after last use.

Opioid Addiction Treatment

Fentanyl and its analogs are schedule II controlled substances in the United States and have a high risk of abuse and dependence. If you become dependent, you may need a medical detox program to address fentanyl withdrawal symptoms.

Fentanyl abuse may also be a sign of a substance use disorder (SUD). Recovery from fentanyl addiction is possible with the help of trained professionals and comprehensive treatment, which may include:

Inpatient Rehab

Inpatient treatment is the most intensive form of treatment and offers 24/7 support. A structured daily schedule may include behavioral therapy, individual counseling, and health activities.

Outpatient Rehab

Outpatient rehab is a more flexible treatment option that allows you to live at home and travel to the treatment center for scheduled sessions. Depending on the severity of addiction and your needs, services may include group therapy, 12-step facilitation, and family therapy.

Medication-Assisted Treatment (MAT)

MAT medications, including methadone and Suboxone (buprenorphine/naloxone), can prevent opioid withdrawal symptoms, including cravings, and reduce the risk of relapse.


Following an intensive treatment program, your aftercare plans may involve sober living options and outpatient counseling to help you transition out of your treatment program.

At Northeast Addictions Treatment Center, we offer a variety of comprehensive outpatient treatment options. If you or a loved one would like to know more about our addiction treatment programs, please contact us today.

Written by
Northeast Addition Editorial Team

Published on

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This page does not provide medical advice.

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