Substance
What not to mix with DXM (robo)
Dissociative
Also calledrobo, robitussin, robotussin, syrup, dex, cough syrup
Cold medicines often add acetaminophen or an antihistamine — check the label
Summary
DXM is checked against 40 other substances — 15 dangerous, 10 unsafe and 3 caution.
Dangerous
15- DXM and AlcoholEach makes the other stronger: you can lose coordination, pass out without warning, and have trouble breathing. Do not combine, and never above the…
- DXM and AMTHigh risk of death or life-changing injury. Do not combine.
- DXM and BuprenorphineTogether they slow breathing and strain the heart and liver, and DXM makes the opioid hit harder. Do not combine. Keep naloxone nearby.
- DXM and CodeineTogether they slow breathing and strain the heart and liver, and DXM makes the opioid hit harder. Do not combine. Keep naloxone nearby.
- DXM and FentanylTogether they slow breathing and strain the heart and liver, and DXM makes the opioid hit harder. Do not combine. Keep naloxone nearby.
- DXM and GHB / GBLBoth wreck coordination and can cause vomiting and unconsciousness, and together they are hard to predict. Do not combine. If someone passes out, put…
- DXM and LithiumTogether they risk serotonin syndrome. Do not combine.
- DXM and MAOIsTogether they carry a high risk of serotonin syndrome. Do not combine.
- DXM and MDMAHigh risk of death or life-changing injury. Do not combine.
- DXM and MephedroneBoth raise serotonin, so together they risk serotonin syndrome, and they also strain the heart. Do not combine.
- DXM and MethadoneTogether they slow breathing and strain the heart and liver, and DXM makes the opioid hit harder. Do not combine. Keep naloxone nearby.
- DXM and OpioidsTogether they slow breathing and strain the heart and liver, and DXM makes the opioid hit harder. Do not combine. Keep naloxone nearby.
- DXM and PCPHigh risk of death or life-changing injury. Do not combine.
- DXM and SSRIsTogether they carry a high risk of serotonin syndrome. Do not combine.
- DXM and TramadolHigh risk of death or life-changing injury. Do not combine.
Unsafe
10- DXM and 2C-T-xRisk of serious physical or psychological harm. Not recommended under any circumstances.
- DXM and 5-MeO-xxTLittle is known about this combination. Avoid it.
- DXM and AmphetaminesBoth raise heart rate, and panic on this mix has led to serious heart problems. Avoid this combination.
- DXM and CocaineBoth raise heart rate, and panic on this mix has led to serious heart problems. Avoid this combination.
- DXM and DiphenhydramineDiphenhydramine raises DXM levels, and together they risk serotonin syndrome, delirium, overheating and heart strain. Avoid this combination at…
- DXM and DOxDOx can hide how much DXM you have taken, which leads to redosing, and DXM can make the DOx very intense. Avoid this combination.
- DXM and MethamphetamineBoth raise heart rate, and panic on this mix has led to serious heart problems. Avoid this combination.
- DXM and MXEBoth act on serotonin, so together they risk serotonin syndrome. Avoid this combination.
- DXM and NBOMesRisk of serious physical or psychological harm. Not recommended under any circumstances.
- DXM and PregabalinEach makes the other stronger, and together they can knock you out and raise the risk of a seizure. Avoid this combination.
Caution
3- DXM and BenzodiazepinesEach makes the other stronger, so high doses can knock you out without warning. Take less of each than usual, and do not use alone. If someone passes…
- DXM and CaffeineA lot of caffeine can make a dissociative trip more anxious and uncomfortable. Keep caffeine light.
- DXM and KratomBoth act on serotonin and both sedate: expect more nausea and dissociation, and serotonin syndrome at higher doses. Take less of each than usual, and…
Low / synergy
8Low / no synergy
4Checking more than one?
This page rates DXM 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 DXM in the checkerOther dissociatives
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.