M. Schori1, D. Pud2, R. Treister3, E. Eisenberg2,4, E. Lawental5. 1School of Social Policy and Practice, University of Pennsylvania, United States; 2Faculty of Social Welfare and Health Sciences, University of Haifa, Israel; 3The Rappaport Faculty of Medicine, Technion–Israel Institute of Technology, Israel; 4Pain Relief Unit, Rambam Medical Center, Israel; 5Department of Social Work, Tel-Hai College, Israel
Background and aims: Compelling evidence has shown that opioids can elicit hyperalgesia (OIH). Recently, we examined the response to cold pain in opioid addict subjects (OAs) and found that the OAs’ mean time for hand withdrawal (tolerance) was significantly shorter than that of drug-naïve controls. In addition, their altered pain perception did not reset 4 weeks subsequent to the cessation of the opioid use. The aim of this study was to explore whether OIH is a reversible phenomenon that may require a long time of abstinence to reset.
Methods: The study included three groups: heroin or methadone addicts (OAs, n=60); former OAs (FOAs) with at least 6 months of drug abstinence who lived at therapeutic communities (FOAs, n=43); and drug-naïve controls (C, n=70). All subjects were exposed to the cold pressor test. Latency of pain onset (seconds) and tolerance were measured.
Results: Mean±standard deviation [SD] time of latencies was 10.8±7.7, 6.9±3.9, and 6.8±3.5 seconds for the OAs, FOAs, and Cs, respectively (p<0.001). Mean±SD tolerance was 30±36.2, 64±58.1, and 56.4±51.4 seconds for the OAs, FOAs, and Cs, respectively (p<0.001). Post hoc analyses revealed that the significant changes were between the OAs and the other two groups in each of the pain variables.
Conclusions: It is suggested that altered pain perception in OAs is a drug-related, reversible phenomenon that may require a long time of abstinence to reset, rather than an individual long-term stable trait.
Financial support: This study was supported by a grant from the Israeli Anti-Drug Authority.