The Effects of Minocycline in Opioid-maintained Patients

Opioids are the most commonly utilized pharmacological treatment for moderate to severe pain. However, their clinical value is hindered by the development of opioid-induced hyperalgesia (OIH). OIH manifests as heightened pain sensitivity, and is an increasingly challenging drawback to the efficacy of opioid treatment. Although the mechanism of action modulating OIH is not completely understood, previous animal studies suggest that this phenomenon is a result of proinflammatory responses. Thus, administering an adjunct anti-inflammatory agent may attenuate OIH. Minocycline is one such agent; it is a tetracycline derivative antibiotic that inhibits microglia activation, nitric oxide (NO) production, and the release of pro-inflammatory cytokines and chemokines. In fact, recent evidence suggests that minocycline may attenuate the neuroinflammatory effects of opioids while enhancing their antinociceptive effects. Therefore, the investigators will determine if minocycline will mitigate OIH in methadone-maintained patients.