Substance
What not to mix with Opioids
OpioidDrug class
Also calledopiate, opiates, opioid, heroin, dope, smack
Full agonists — heroin, oxycodone, morphine
Summary
Opioids is checked against 40 other substances — 13 dangerous, 3 unsafe and 8 caution.
Dangerous
13- Opioids and AlcoholBoth substances potentiate the ataxia and sedation caused by the other and can lead to unexpected loss of consciousness at high doses. Place the…
- Opioids and BenzodiazepinesCentral nervous system and/or respiratory-depressant effects may be additively or synergistically present. The two substances potentiate each other…
- Opioids and CocaineStimulants increase respiration rate allowing for a higher dose of opiates than normal. If the stimulant wears off first then the opiate may overcome…
- Opioids and CodeineStacking codeine onto a stronger opioid adds meaningful respiratory depression for very little extra effect — the worst possible ratio. Codeine is…
- Opioids and DXMCNS depression, difficult breathing, heart issues, hepatoxic, just very unsafe combination all around. Additionally if one takes DXM, their tolerance…
- Opioids and FentanylTolerance built on heroin or oxycodone does not translate cleanly to fentanyl, and fentanyl is increasingly what is actually in both. Stacking them…
- Opioids and GHB / GBLThe two substances potentiate each other strongly and unpredictably, very rapidly leading to unconsciousness. While unconscious, vomit aspiration is…
- Opioids and KetamineBoth substances bring a risk of vomiting and unconsciousness. If the user falls unconscious while under the influence there is a severe risk of vomit…
- Opioids and KratomKratom is often taken to take the edge off between doses or to self-manage withdrawal, which puts it in the same window as a full agonist far more…
- Opioids and MethadoneUsing heroin or oxycodone on top of methadone is dosing into an opioid load that is still there whether or not you feel it. Because methadone blunts…
- Opioids and MXEThis combination can potentiate the effects of the opioid
- Opioids and PregabalinHigh risk of death or life-changing injury. Do not combine.
- Opioids and TramadolConcomitant use of tramadol increases the seizure risk in individuals taking other opioids. These agents are often individually epileptogenic and may…
Unsafe
3- Opioids and BuprenorphineBuprenorphine outcompetes heroin, oxycodone and morphine at the receptor while producing much weaker signalling than they do, so taking it on top of…
- Opioids and DiphenhydramineBoth substances are CNS depressants, potentiating each other strongly and unpredictably, raising the chances of memory loss, severe ataxia, and…
- Opioids and MethamphetamineA stimulant masking opioid sedation is how people miss the point at which they are overdosing. Methamphetamine's long duration means the opioid is…
Caution
8- Opioids and AcetaminophenMost prescription opioid tablets (Percocet, Vicodin, Norco, some codeine formulations) are combination products that already contain acetaminophen…
- Opioids and AmphetaminesStimulants increase respiration rate, which can allow for a higher dose of opiates normal . If the stimulant wears off first then the opiate may…
- Opioids and LithiumNo direct pharmacokinetic interaction, but additive sedation and any dehydration or reduced kidney perfusion can raise lithium levels. Note that…
- Opioids and MAOIsCoadministration of monoamine oxidase inhibitors (MAOIs) with certain opioids has been associated with rare reports of severe and fatal adverse…
- Opioids and MelatoninAdditive sedation on top of an opioid's respiratory depression. Melatonin is not the main risk in this stack, but it deepens sedation and makes an…
- Opioids and MephedroneStimulants increase respiration rate allowing a higher dose of opiates. If the stimulant wears off first then the opiate may overcome the patient and…
- Opioids and Nitrous OxideBoth substances potentiate the ataxia and sedation caused by the other and can lead to unexpected loss of consciousness at high doses. While…
- Opioids and PCPPCP can reduce opioid tolerance, increasing the risk of overdose
Low / synergy
1Low / no synergy
15Checking more than one?
This page rates Opioids 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 Opioids 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.