States eye adding gabapentin to controlled substance list

Gabapentin is a popular medication for treating neuropathic pain and epilepsy, but reports of illicit use of the drug are on the rise. Although gabapentin can be used alone, most cases of its misuse also involve opioids, benzodiazepines or alcohol, and the results can be fatal.

In response to a rise in drug deaths involving gabapentin, some states—including Kentucky, Ohio, and West Virginia—are adding the medication to controlled substance rosters. Gabapentin is not currently a federally scheduled drug.

Gabapentin is the seventh most commonly prescribed medication in the United States, according to a ranking from GoodRx. It debuted in 1993 and is approved by the Food and Drug Administration (FDA) for treating neuralgia and epilepsy, but off-label uses can include the treatment of migraines, bipolar disorder, and anxiety disorders. A gabapentinoid, gabapentin has pharmacokinetic properties similar to those of pregabalin, which is listed by the Drug Enforcement Administration (DEA) as a Schedule V controlled substance.

The FDA cautions that gabapentin can increase the effect of opioids and other drugs, and a body of recent research backs the warning. A 2016 report published in Addiction found that about 40 to 65% of individuals prescribed gabapentin misuse it, and 15 to 22% of persons with an opioid abuse problem also abuse gabapentin. Abuse usually was attributed to recreational use, self-medication or intentional self-harm, and the drug often was used in combination with opioids, benzodiazepines and/or alcohol, according to the report.

Another study, published this year in PLOS Medicine, found that gabapentin use alongside prescription opioid use resulted in a “substantial increase” in the risk of opioid-related death. The authors concluded that opioid-related deaths were 49% higher in individuals recently exposed to a combination of opioids and gabapentin than in those taking opioids alone. Moderate to high doses of gabapentin (900 mg or more daily) were associated with a 60% increase in the odds of opioid-related death when compared with opioid use alone.

The authors of the study recommended careful consideration when prescribing gabapentin alongside opioids, careful monitoring when the combination is necessary, and possible adjustments to opioid doses when the drugs are used with gabapentin.

Abuse potential

Concerns around gabapentin do not involve prescriptions only. There is anecdotal evidence that gabapentin is attractive for abuse because it often isn’t included in drug testing, can be relatively easily acquired, and can intensify the effects of other drugs. According to a February 2017 report from the Ohio Department of Mental Health & Addiction Services, gabapentin was once thought to have a low abuse profile, but reports from law enforcement suggest that misuse is rising quickly. Ohio, Kentucky and West Virginia all have recently moved gabapentin onto their controlled substance list; each of these states has documented spikes in opioid deaths involving gabapentin.

Other states have at least required that prescriptions of gabapentin be tracked through the state’s prescription drug monitoring program.

Kirk Evoy, PharmD, clinical assistant professor of pharmacology at the University of Texas at Austin and an adjoint assistant professor in the School of Medicine at the University of Texas Health Science Center at San Antonio, says the reasons why gabapentin misuse is growing are open to speculation. Prescribers and those monitoring patients on gabapentin seem somewhat unaware of the trend, he says, but adding gabapentin to a controlled substance list would remedy that.

There also are downsides to making gabapentin a controlled substance, however. For one, it would make it more difficult to prescribe and dispense the drug to patients who need it, Evoy says. There is a balance, he says, in curtailing abuse while also avoiding disruption to therapeutic regimens and not adding to the already heavy burden of drug reporting.

“Are we putting too much regulation on drugs that are commonly used, and does that put a lot of extra work on pharmacies and doctors?” Evoy asks, adding that these are questions with which stakeholders are grappling.

Also, “There are other drugs that can be abused. If you try to limit one it doesn’t mean you can’t find other things to abuse,” Evoy says. “Could it help with the problem and help providers be more aware? That could be true. Provider education is going to be a big part of it, too.”

Evoy is working with other pharmacists to increase awareness of gabapentin abuse. In the meantime, a report published last month in Expert Opinion on Drug Safety states that piecemeal legislation on a state-by-state basis might not be the answer. The report suggests that a unified national approach that includes federal regulation and enhanced monitoring might be most effective.