Substance
What not to mix with Fentanyl
Opioid
Also calledfent, fentanil, carfentanil, nitazene, nitazenes, duragesic
Synthetic — potent by micrograms, unevenly mixed
Summary
Fentanyl is checked against 40 other substances — 12 dangerous, 4 unsafe and 6 caution.
Dangerous
12- Fentanyl and AlcoholFentanyl doses vary wildly even within one batch, and alcohol removes whatever margin is left. Do not combine. If you use anyway: never in the same…
- Fentanyl and BenzodiazepinesThe deadliest pairing in current overdose data: people simply stop breathing, often silently. Do not combine. If you use anyway, never alone, and…
- Fentanyl and CodeineFentanyl sets the risk; codeine adds little effect and real danger. Do not combine. Keep naloxone nearby.
- Fentanyl and DXMTogether they slow breathing and strain the heart and liver, and DXM makes the opioid hit harder. Do not combine. Keep naloxone nearby.
- Fentanyl and GHB / GBLBoth have almost no margin, and naloxone reverses the fentanyl but does nothing for the GHB. Do not combine.
- Fentanyl and KetamineTogether they can cause vomiting and unconsciousness. Do not combine. Keep naloxone nearby, and put anyone who passes out on their side.
- Fentanyl and KratomKratom does nothing to blunt fentanyl; fentanyl sets the risk here. Do not combine. Never use alone, and keep naloxone nearby.
- Fentanyl and MethadoneYesterday's methadone is still active, and fentanyl on top of it is a common way people die, especially in the first two weeks of treatment. Do not…
- Fentanyl and MXEMXE can make the opioid hit harder. Do not combine. Keep naloxone nearby.
- Fentanyl and OpioidsYour tolerance to heroin or pills does not carry over cleanly to fentanyl, which is increasingly what is in both anyway. Do not combine. Never use…
- Fentanyl and PregabalinPregabalin carries an FDA warning for slowed breathing with opioids, and its sedation peaks late. Do not combine. Keep naloxone nearby.
- Fentanyl and TramadolTramadol raises the seizure risk, and together they can slow breathing. Do not combine. Keep naloxone nearby.
Unsafe
4- Fentanyl and BuprenorphineBuprenorphine knocks fentanyl off the receptor and can throw you into sudden, severe withdrawal. If you are starting buprenorphine after fentanyl, do…
- Fentanyl and CocaineCocaine hides how sedated you are; it wears off within the hour while fentanyl keeps working, and breathing can stop. Avoid this combination. Test…
- Fentanyl and DiphenhydramineEach makes the other stronger, raising the risk of memory loss, collapse and unconsciousness. Avoid this combination. Keep naloxone nearby.
- Fentanyl and MethamphetamineMeth hides the fentanyl for hours, so people redose it, and when the meth fades the whole load hits. Avoid this combination. If you use anyway, never…
Caution
6- Fentanyl and AmphetaminesThe stimulant hides how much the opioid is slowing you; if it wears off first, breathing can stop. Take less of each than usual, do not use alone…
- Fentanyl and LithiumTogether they add sedation, and dehydration can push lithium levels up. Keep up water, and keep naloxone nearby.
- Fentanyl and MAOIsWith certain opioids, MAOIs have caused rare but severe and fatal reactions. Take less of each than usual, do not use alone, and keep naloxone nearby.
- Fentanyl and MephedroneThe stimulant hides how much the opioid is slowing you; if it wears off first, breathing can stop. Take less of each than usual, do not use alone…
- Fentanyl and Nitrous OxideEach makes the other stronger, so you can lose balance or pass out without warning. Take less of each than usual, do not use alone, and keep naloxone…
- Fentanyl and PCPPCP can lower your opioid tolerance, making an overdose more likely. Take less opioid than usual, do not use alone, and keep naloxone nearby.
Low / synergy
1Low / no synergy
17Checking more than one?
This page rates Fentanyl against one substance at a time. Combinations of three or more carry risks that no pair-by-pair list can show — the checker rates every pair at once and flags the whole-mix ones on top.
Open Fentanyl in the checkerOther opioids
All combinations →Educational information only, not medical advice. Absence of a documented interaction is not evidence of safety. Combination data from the TripSit drug combination chart, retrieved 2026-08-20.