Fentanyl

Opioid · popular

A synthetic opioid measured in micrograms, 50-100x morphine potency. It contaminates counterfeit pills and other powders. Overdose can be immediate and requires naloxone plus emergency services.

fentanilSublimazeActiqDurogesicDuragesicFentoraMatrifenHaldidOnsolisInstanylAbstralLazanda

Dose and effect data: PsychonautWiki (CC BY-SA 4.0) and TripSit (PolyForm Noncommercial 1.0.0).

Before you dose

⚠Dose here depends overwhelmingly on your tolerance, not your body weight. A dose that is mild for a tolerant user can be fatal for someone else.

⚠This substance has combinations that are life-threatening. Check the Interactions tab before mixing anything.

Dose

Published population range

Threshold5 μg

Light10–25 μg

Common25–50 μg

Strong50–75 μg

⚠Microgram-level accuracy is impossible with street equipment, which is why there is no safe way to use this.

Basis: No weight-based model is meaningful.

Fentanyl and nitazenes are active in microgram amounts and are routinely pressed into counterfeit pills and mixed into other powders.

Check an amount you already have

Timeline (insufflated)

Onset15–30 minutes

Total60–240 minutes

Bars show relative time in each phase, scaled to the total duration. Each phase keeps its colour in the list above.

Expected effects

Very intense euphoria (brief)
Analgesia
Sedation

Possible side effects

Immediate risk of fatal respiratory depression
Overdose from doses measured in micrograms
Contamination of counterfeit pills and other powders
Rapid dependence
Naloxone may need multiple doses

Known toxicity

potentially fatal at heavy dosages
potentially lethal when mixed with depressants like alcohol or benzodiazepines
unintentionally transporting the substance from the skin by touching the mouth, nose or eyes is dangerous

Harm reduction

There is no reliable way to eyeball a dose. Assume any powder or pill could contain it.
Never use alone, and carry naloxone - it usually needs more than one dose for fentanyl and nitazenes.
Do not combine with benzodiazepines, alcohol or GHB.
If you are using again after any break, start with a fraction of your previous dose.
Never use alone. The single most effective thing you can do is have someone with you or on the phone.
Carry naloxone and know how to use it. It reverses opioid overdose and cannot harm someone who has not taken opioids.
Use fentanyl and nitazene test strips on every batch, including pills. They catch a large share of contamination, though not all of it.
Start with a fraction of your usual amount when you get a new batch or after any break in use - tolerance drops fast, in days.
Do not mix with benzodiazepines, alcohol, GHB or other sedatives. That combination is behind the majority of opioid deaths.
If someone is unresponsive: call emergency services, give naloxone, put them in the recovery position and stay with them. Naloxone wears off before many opioids do, so a second dose may be needed.

Identify what you have

Marquis (reacts)orange > brown (116)

Mecke (reacts)clear or green (63)

Mandelin (reacts)olive green (14)

Reagent tests show what a substance probably is, not how pure it is or what else is in the mix. Fentanyl and nitazene test strips are the only reliable check for those, and quantitative lab testing is better than both.