Effects of gabapentin on heroin and cocaine self-administration in rats

Reports of gabapentin misuse among people with opioid use disorder have increased, as has the presence of gabapentin in opioid overdose deaths. Despite these trends and known interactions between these drugs in other settings (e.g. gabapentin as an 'opioid-sparing' agent), few studies have evaluated the impact of gabapentin on reinforcing effects of opioids. Intravenous self-administration in rats was used to determine whether gabapentin modifies the reinforcing effects of heroin or cocaine. Rats self-administered drugs under a progressive ratio schedule of reinforcement after saline or gabapentin pretreatment. Pretreatment with 32 mg/kg gabapentin increased the number of infusions earned on the ascending limb of the heroin dose-response curve but had no effect on cocaine self-administration. While the magnitude of effect was modest, these data suggest that gabapentin can potentiate the reinforcing effects of opioids and lays the groundwork for future studies characterizing interactions between gabapentinoids and opioids in the context of reinforcement.