A growing number of animal and human studies show that under certain circumstances, opioids can elicit unexpected changes in pain sensitivity, resulting in hyperalgesia (abnormally intense pain in response to painful// stimulation) and allodynia (abnormally intense pain in response to non-painful stimulation).
Interestingly, previous studies have found evidence for hyperalgesia only subsequent to brief exposure to opioid treatment. No reports of hyperalgesia following the prolonged administration of opioids for the treatment of chronic or cancer pain have yet been published. However, using the cold pressor test (CPT), several studies have suggested that opioid addicts (OAs) may exhibit hyperalgesia as shown by their ability to maintain their hand in ice-cold water for a significantly shorter duration than were healthy controls.
Recent evidence reported on increased pain sensitivity in animals following parenteral opioid administration and in humans subsequent to intravenously of short-acting opioids and possibly in drug addicts.
A new study, to be published in Drug and Alcohol Dependence (available online 17 October 2005) was designed with the objectives to test if drug addicts, while actively consuming opioids, differ from normal subjects in their latency of pain onset, pain intensity, or time required for hand withdrawal in response to the CPT; and, if indeed so, to determine whether the discontinuation of opioid consumption will reset their altered pain responses.
For the study, 60 heroin or methadone OAs who attended a 4-week inpatient detoxification program were exposed to the cold pressor test (CPT) upon entrance to the program, at 7 and 28 days subsequent to the cessation of opioid consumption (verified by repeated urine toxicology tests).
Latency of pain onset (s), pain intensity (0–100 VAS), and tolerance (time for hand withdrawal) in response to the CPT were measured. The main findings of this study were tPage: 1 2 Related medicine news :1
. Back pain treated with Opioids 2
. Opioids Linked to Worse Outcomes After Back Injury3
. Prescription Opioids Abused More Than Heroin - A Report Says4
. Early Detection Of Facial Abnormalities in a Fetus5
. Abnormal Brain Structure One Of The Reasons For Depression in Adolescents6
. Antidepressants Could Lead To Abnormal Bleeding7
. Abnormal heart rate and depression may increase death risk8
. Cancer Causing Proteins Trigger Abnormal Biochemical Reactions In Cells9
. Neglect In Childhood Could Cause Abnormal Behaviour In Adults10
. Detecting Brain Abnormalities in Babies Using New Brain Scanners.11
. New Abnormal Karyotypes Discovered in China