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How Long Does Fentanyl Stay In Your System

What is fentanyl

Fentanyl is a synthetic opioid analgesic that was first synthesized by Paul Janssen, founder of Janssen Pharmaceutica. It has been used to treat moderate to severe pain in recent times but was also used as an anesthetic in the 1960s under the brand name ‘Sublimaze’. It is a hundredfold more potent than morphine and also has around 40-50 times more potency than pharmaceutical heroin.



How long does fentanyl stay in your urine, blood, saliva and hair follicle

Urine Test 8-24 hours
Blood Test 12 hours
Saliva Test Up to 3 days
Hair Follicle Test Up to 3 months, i.e. 90 days.


How long can the different forms of fentanyl show up on a drug test

Fentanyl Patch 2.98-5 days
Fentanyl Lozenge 1.15-3.43 days
Intravenous Fentanyl 11-22 hours

To understand how long fentanyl would stay in your system after you have stopped taking it, we must first take into account its elimination half-life.  Each format of fentanyl, whether it be transdermal patches, transmucosal lozenges or intravenous administration has different half-life duration than the other.

IV fentanyl has an elimination half-life of around 2-4 hours. Like most drugs, fentanyl generally exhibits about 5.5 half-lives, it can be concluded that intravenously administered fentanyl would take around 11 to 22 hours to be completely eliminated from the blood plasma.

A transdermal patch is believed to have a much longer elimination half-life than the intravenous variant, clocking at around 13-22 hours, this puts the amount of time required by the system to process fentanyl and its eventual excretion at around 2.98-5 days.

The transmucosal fentanyl variant has an elimination half-life of 5-15 hours, thereby requiring 1.15-3.43 days for its full elimination.

It must be, however, noted that these timeframes may vary from person to person depending on certain individual factors like age, build, genetics, hydration levels, liver and kidney conditions, BMR. It must also be taken into consideration that how long the person has been on fentanyl for, how the drug has been administered to them, the amount of dosage, and of course, whether any other drugs are being co-administered, that might help or hinder the metabolism of fentanyl.

How to pass a fentanyl drug test

  • Increase physical activities – A higher body fat percentage would mean longer time periods for fentanyl elimination from your system. One way to negate this is to be physically active, exercise and work-out more, this will lead to the reduction of body fat, thereby helping in the elimination of fentanyl from your body.
  • Using Calcium-D-Glucarate – This cellular detoxifying agent aids in the elimination of toxins from your liver and kidneys. It can be used to eliminate the toxins that result from fentanyl ingestion, including its subsequent metabolites.

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