Opiate addiction disorders associated with opioid-induced hyperalgesia

Patients with addictive disorders who take methadone or other opioid medications for pain will experience heightened sensitivity to pain, known as hyperalgesia, and new research published in The Journal of Pain shows that the condition does not improve over the course of treatment.

Managing pain in heroin-abusing patients poses challenges for clinicians because they present for treatment in a hyperalgesic state and maintenance therapy with either methadone or buprenorphine does not change their pain responses. Opioid medications not only provide rapid pain relief but also induce hyperalgesia, which has been suggested to contribute to opioid tolerance. Previous research has shown that patients taking methadone for heroin addiction are significantly more sensitive to pain than drug-free individuals.

For this study, researchers from UCLA compared the pain responses of treatment seeking, heroin-addicted patients to a non-drug control group using experimental pain stimuli. They sought to determine how hyperalgesia might change as a patient moves from heroin abuse to stabilization and eventually to maintenance on a pain treatment opioid.

Eighty-two heroin-addicted subjects and a drug free control group participated in the study. Those who were abusing heroine were given either methadone or buprenorphine, and the cold pressor test and electrical stimulation were administered to measure pain responses.

Results showed that maintenance therapy with either methadone or buprenorphine for hyperalgesic heroin-dependent individuals did not significantly change or worsen their pain responses. Based on these findings, the authors recommend that clinicians consider the potential impact of opioid-induced hyperalgesia associated with opiate addiction disorders when treating patients who use opiates legitimately or illicitly.