These combinations are not usually physically harmful, but may produce undesirable effects. Use caution.
Note: Stimulants increase respiration rate allowing a higher dose of opiates. If the stimulant wears off first then the opiate may overcome the patient and cause respiratory arrest.
Substances in these categories
Mephedrone
Opioids
Sources
- Opioid Analgesics. In StatPearls. — Cohen, B., Ruth, L. J., & Preuss, C. V. (2025)
- The pharmacology and toxicology of the synthetic cathinone mephedrone (4‐methylmethcathinone). Drug Testing and Analysis, 3(7–8), 454–463. — Dargan, P. I., Sedefov, R., Gallegos, A., & Wood, D. M. (2011)
- 4-Methylmethcathinone (Mephedrone): Neuropharmacological Effects of a Designer Stimulant of Abuse. The Journal of Pharmacology and Experimental Therapeutics, 339(2), 530–536. — Hadlock, G. C., Webb, K. M., McFadden, L. M., Chu, P. W., Ellis, J. D., Allen, S. C., Andrenyak, D. M., Vieira-Brock, P. L., German, C. L., Conrad, K. M., Hoonakker, A. J., Gibb, J. W., Wilkins, D. G., Hanson, G. R., & Fleckenstein, A. E. (2011)
- Mephedrone, compared with MDMA (ecstasy) and amphetamine, rapidly increases both dopamine and 5-HT levels in nucleus accumbens of awake rats: Mephedrone increases both DA and 5-HT in rat brain. British Journal of Pharmacology, 164(8), 1949–1958. — Kehr, J., Ichinose, F., Yoshitake, S., Goiny, M., Sievertsson, T., Nyberg, F., & Yoshitake, T. (2011)
- Mephedrone, a new designer drug of abuse, produces acute hemodynamic effects in the rat. Toxicology Letters, 208(1), 62–68. — Meng, H., Cao, J., Kang, J., Ying, X., Ji, J., Reynolds, W., & Rampe, D. (2012)
- Basic opioid pharmacology: an update. British Journal of Pain, 6(1), 11–16. — Pathan, H., & Williams, J. (2012)
Interaction Matrix
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These drugs work together to cause an effect greater than the sum of its parts. They aren't likely to cause an adverse or undesirable reaction when used carefully.
Effects are additive. The combination is unlikely to cause any adverse or undesirable reaction beyond those that might ordinarily be expected from these drugs.
One substance may reduce or counteract some of the effects of the other.
These combinations are not usually physically harmful, but may produce undesirable effects. Use caution.
There is considerable risk of physical harm when combining these substances. Use extreme caution.
These combinations are considered dangerous and should be avoided.
The interactions between these substances are not well documented.