Predictors and motives of polydrug use in opioid users. A narrative review

To review the recent literature on predictors and personal motives of polydrug use in opioid users with a focus on combined use of opioids with stimulants, benzodiazepines and gabapentinoids.

In North America, methamphetamine is now the most prevalent co-drug in opioid users and is responsible for high mortality rates. In Europe, opioids are rather combined with either cocaine, benzodiazepines or gabapentionoids, but recent data are lacking.Main personal motives of opioid users to combine opioids with methamphetamine or cocaine is to boost the opioid high, inhibit the withdrawal effects of heroin and have a cheaper alternative to maintain the opioid high. Risk factors of polydrug use by opioid users included being male, younger age, homelessness, high-risk sexual behavior, needle sharing, incarceration, poor mental health and recent use of cocaine or prescription opioids. The motives for co-use of opioids and gabapentinoids also include seeking a better high, lower price and to self-medicate pain/physical symptoms, including those resulting from withdrawal.

When treating opioid users with polydrug drug use, special attention should be paid to dosing when in opioid agonist methadone/buprenorphine treatment and to the presence of physical pain. The validity of part of the personal motives seems questionable which deserves attention when counselling opioid users with polydrug use.