Substance
What not to mix with Codeine
Opioid
Also calledlean, purple drank, co-codamol, dihydrocodeine
Weak, but metabolised unpredictably between people
Summary
Codeine is checked against 40 other substances — 12 dangerous, 3 unsafe and 9 caution.
Dangerous
12- Codeine and AlcoholThe lean pairing, and the reason it kills people who thought they were being moderate. Codeine's conversion to morphine varies enormously between…
- Codeine and BenzodiazepinesAdditive respiratory depression, made worse by codeine's unpredictable conversion. A dose that was fine last time can convert very differently…
- Codeine 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…
- Codeine and DXMCNS depression, difficult breathing, heart issues, hepatoxic, just very unsafe combination all around. Additionally if one takes DXM, their tolerance…
- Codeine and FentanylAdditive respiratory depression, with fentanyl setting the risk. Codeine adds little effect and meaningful danger.
- Codeine and GHB / GBLThe two substances potentiate each other strongly and unpredictably, very rapidly leading to unconsciousness. While unconscious, vomit aspiration is…
- Codeine 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…
- Codeine and MethadoneAdditive respiratory depression on top of methadone's accumulating baseline, for very little added effect.
- Codeine and MXEThis combination can potentiate the effects of the opioid
- Codeine and OpioidsStacking codeine onto a stronger opioid adds meaningful respiratory depression for very little extra effect — the worst possible ratio. Codeine is…
- Codeine and PregabalinHigh risk of death or life-changing injury. Do not combine.
- Codeine and TramadolConcomitant use of tramadol increases the seizure risk in individuals taking other opioids. These agents are often individually epileptogenic and may…
Unsafe
3- Codeine and DiphenhydramineBoth substances are CNS depressants, potentiating each other strongly and unpredictably, raising the chances of memory loss, severe ataxia, and…
- Codeine and KratomAdditive opioid effect with two unpredictable variables stacked: kratom products vary widely in alkaloid content between batches, and codeine's…
- Codeine 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
9- Codeine and AcetaminophenNot an interaction between the drugs so much as a counting problem that sends people to hospital. Most codeine sold over the counter is a combination…
- Codeine 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…
- Codeine and BuprenorphineBuprenorphine largely blocks codeine's effect. The realistic outcome is that codeine does nothing useful, plus mild withdrawal if buprenorphine has…
- Codeine and LithiumNo direct pharmacokinetic interaction, but additive sedation and any dehydration or reduced kidney perfusion can raise lithium levels. Note that…
- Codeine and MAOIsCoadministration of monoamine oxidase inhibitors (MAOIs) with certain opioids has been associated with rare reports of severe and fatal adverse…
- Codeine 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…
- Codeine 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…
- Codeine and PCPPCP can reduce opioid tolerance, increasing the risk of overdose
- Codeine and SSRIsFluoxetine and paroxetine strongly inhibit CYP2D6, the enzyme that turns codeine into morphine. The usual result is that codeine stops working, which…
Low / synergy
1Low / no synergy
15Checking more than one?
This page rates Codeine 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 Codeine 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.