Gabapentin improves cold-pressor pain responses in methadone-maintained patients

• Published in: Drug and alcohol dependence Vol. 109; no. 1; pp. 213 - 219
• Main Authors: Compton, Peggy, Kehoe, Priscilla, Sinha, Karabi, Torrington, Matt A., Ling, Walter
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 01.06.2010; Elsevier
• Subjects: Addictive behaviors; Adult; Adult and adolescent clinical studies; Amines - adverse effects; Amines - pharmacology; Analgesics, Non-Narcotic - adverse effects; Analgesics, Non-Narcotic - pharmacology; Biological and medical sciences; Cold Temperature; Cyclohexanecarboxylic Acids - adverse effects; Cyclohexanecarboxylic Acids - pharmacology; Double-Blind Method; Drug addiction; Female; Gabapentin; gamma-Aminobutyric Acid - adverse effects; gamma-Aminobutyric Acid - pharmacology; Humans; Hyperalgesia; Hyperalgesia - drug therapy; Hyperalgesia - etiology; Male; Medical sciences; Methadone; Methadone - adverse effects; Methadone - blood; Methadone - therapeutic use; Middle Aged; Narcotics - adverse effects; Narcotics - blood; Narcotics - therapeutic use; Nervous system; Opioid-Related Disorders - rehabilitation; Pain; Pain Measurement - drug effects; Pain Threshold - drug effects; Patient Compliance; Plasma levels; Pressure; Psychiatry; Psychology. Psychoanalysis. Psychiatry; Psychopathology. Psychiatry; Thresholds; Treatment; Treatment; Methadone; Gabapentin; Hyperalgesia; Human; Drug addiction; Temperature; Cold; Environmental factor; Opiates; Patient; Anticonvulsant; Narcotic analgesic; Response; Improvement; Pain; Addiction
• ISSN: 0376-8716; 1879-0046; 1879-0046
• DOI: 10.1016/j.drugalcdep.2010.01.006

Individuals on methadone maintenance for the treatment of addiction (MM) are demonstrated to be hyperalgesic to cold-pressor pain in comparison to matched controls and ex-opioid addicts, a finding described as clinical evidence of opioid-induced hyperalgesia (OIH). Interestingly, opioids induce hyperalgesia via many of the same neuro-inflammatory and central sensitization processes that occur with the development of neuropathic pain. Evaluated in this study was the efficacy of a key pharmacotherapy for neuropathic pain, gabapentin (GPN), to reverse OIH in MM patients. Utilizing a clinical trial design and double blind conditions, changes in cold-pressor pain threshold and tolerance following a 5-week trial of GPN (titrated to 2400 mg/day) were evaluated at peak and trough methadone plasma levels in a well-characterized MM sample. Drug abstinence was encouraged via an escalating payment schedule, and compliance monitored via pill counts and GPN plasma levels; entered into the analyses were only those subjects compliant and abstinent throughout the study (approximately 45%). Utilizing change scores from baseline, significant improvements in cold-pressor pain threshold and pain tolerance were observed at both peak and trough methadone levels ( p < 0.05). Notably, drop-out rates due to medication side effects were low (2%) and the medication was well-tolerated. These results support that GPN, as prescribed for the treatment of neuropathic pain, is effective in decreasing OIH in patients who are abstinent and stable in methadone treatment.