Abstract
BACKGROUND: Recent data suggest that glial cells may be involved in the analgesic effects and abuse liability of opioids. Preclinical studies have demonstrated that mu-opioid-receptor-selective agonists, such as oxycodone, activate glia and increase the release of cytokines, causing a suppression of opioid-induced analgesic effects. Preclinical studies also show that certain medications, such as the broad-spectrum tetracycline antibiotic minocycline, inhibit opioid-induced glial activation and thereby enhance the analgesic effects of opioids. Importantly, minocycline reduces the rewarding effects of opioids at the same doses that it enhances opioid-induced analgesia. AIMS: The purpose of the present study was to assess the effects of acute administration of minocycline on the subjective, physiological, and analgesic effects of oxycodone in human research volunteers. DESIGN: This study was a within-subject, randomized, double-blind outpatient study. Participants completed five separate sessions in which they received 0, 100, or 200 mg minocycline (MINO) simultaneously with either 0 or 40 mg oxycodone (OXY). The subjective, physiological, and analgesic effects of OXY were measured before and repeatedly after drug administration. SETTINGS AND PARTICIPANTS: Participants were between 21 and 45 years of age, non-treatment seeking, non-dependent recreational opioid users (N = 12). This study was conducted between 2013 and 2014 at the New York State Psychiatric Institute in New York, NY. FINDINGS: MINO 100 and 200 mg were safe and well-tolerated in combination with OXY 40 mg. MINO 200 mg administered with OXY 40 mg attenuated OXY-induced positive subjective effects such as "Good Effect" and "Liking" compared to OXY alone. MINO did not alter the physiological or analgesic effects of OXY. CONCLUSIONS: MINO may attenuate the abuse liability of mu-opioid-receptor-selective agonists.