ABSTRACT/SUMMARY
This application from a “New Investigator” is in response to Parent Announcement PA-20-185 “NIH Research
Project Grant (Parent R01 Clinical Trial Not Allowed)” and requests 5 years of support to study the contribution
of gabapentinoids to the opioid crisis. The number of opioid overdoses and deaths continues to increase despite
a significant decrease in the number of prescriptions for opioids. At the same time, the use of gabapentinoids
(gabapentin [Neurontin®]) and pregabalin [Lyrica®]) has increased significantly. Although typically prescribed
to treat seizures and convulsions, increasingly gabapentinoids are used off-label as alternatives to opioids and
there is mounting concern that misuse of gabapentinoids is contributing to opioid-induced morbidity and
mortality. Pregabalin is classified as a Schedule V controlled substance by the Drug Enforcement Administration
(DEA). Although gabapentin currently is not scheduled by the DEA, it is scheduled in five states and there is
mounting pressure from various consumer and advocacy groups for the DEA to schedule gabapentin. These
drugs appear to pose a significantly greater risk to public health than has thought to be the case, particularly
because gabapentinoids are increasingly detected in opioid overdose victims. Because they are presumed to be
very safe and not likely to be abused, little is known about the potential risk of gabapentinoids when used with
other drugs, including the following: 1) whether gabapentinoids enhance the abuse related and/or toxic effects
of opioids; 2) whether a history of opioid use increases the likelihood of misuse of gabapentinoids; and 3) whether
gabapentinoids cause physical dependence and/or impact opioid physical dependence. Our pilot studies show
that gabapentinoids reduce the potency of naloxone to reverse ventilatory depression by heroin and increase the
potency of fentanyl in a drug discrimination assay. Proposed studies address the paucity of information regarding
potential adverse effects of gabapentinoids, particularly in combination with opioids, and explore three specific
aims that test the following hypotheses: 1) gabapentinoids reduce the potency of naloxone to reverse the
ventilatory-depressant effects of mu opioid receptor agonists; 2) a history of opioid exposure
unmasks/enhances the positive reinforcing effects of gabapentinoids; and 3) gabapentinoids attenuate opioid
withdrawal, and exacerbate opioid physical dependence. Because this is an unexplored area of research, it is
unclear whether gabapentinoid/opioid interactions are sex dependent. By systematically comparing the effects
of gabapentinoids and opioids, alone and in mixtures, in female and male rats, these studies will provide a much-
needed comprehensive assessment of the risk potential (ventilatory depression, self-administration,
reinstatement, drug discrimination, and physical dependence) of gabapentinoids when used in combination with
opioids. The opioid crisis has worsened significantly during the pandemic and previously unappreciated forms
of drug use (e.g., increasing use of gabapentinoids in individuals also taking opioids) demand our attention in
order to address this growing national public health crisis that is decreasing the life expectancy of Americans.