Mixing Diphenhydramine and Opioids
- Diphenhydramine also called
- benadryl, dph, sleep aid, zzzquil, unisom
- Opioids also called
- opiate, opiates, opioid, heroin, dope, smack
Unsafe
Both substances are CNS depressants, potentiating each other strongly and unpredictably, raising the chances of memory loss, severe ataxia, and unconsciousness. The interaction will cause greater inhibition and risk of injury. DPH reduces histamine release by opioids, which reduces the itching side effect from opioids. DPH may reduce the nausea caused by opioids. DPH inhibits CYP2D6 activity which can lead to a reduction of effects in some opioids and potentiation of effects in others.
This combination carries bodily risk and can go badly psychologically. The headspace part often arrives first and makes the physical part harder to notice.
Can you mix Diphenhydramine and Opioids?
Risk of serious physical or psychological harm. Not recommended under any circumstances.
- Opioids
- Full agonists — heroin, oxycodone, morphine
TripSit drug combination chart, retrieved 2026-08-20. View the dataset.
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Rated unsafe. Educational information only, not medical advice. Absence of a documented interaction is not evidence of safety.