How Classifying Gabapentin as Schedule V Could Help Support the Fight Against the Opioid Epidemic

Pharmacy Times interviewed Michael Abrams, MPH, PhD, senior health researcher at Public Citizen’s Health Research Group, to discuss his petition to the DEA and FDA regarding the classification of gabapentin and the closely related drugs, gabapentin enacarbil, as schedule V controlled substances.

Alana Hippensteele: So, Michael, why might classification of these drugs as schedule V be beneficial?

Michael Abrams: Thanks, Alana, and thanks for the interest in the petition and for having me. So, putting a drug on schedule V—what does it do? In a phrase: It allows for surveillance and control by the FDA and the DEA, especially, and activities that would occur at the federal level, including things like monitoring the distribution of the drug and controls on prescribing.

So, this doesn't mean banning the drug by any means. It just means posing some commonsense limits on how much is prescribed at one time, how long one has that prescription before they must refill it, pill counts—things that allow for the prescriber and the patient to guard against potentially dangerous problems that might exist with a drug.

In the case of the kinds of drugs that the DEA has the imprimatur over, if you will, or the responsibility over, and by connection to the FDA as well—these are drugs that often act on the central nervous system. There's high risk of abuse, addiction diversion, and in the case of gabapentin, there's also a risk of respiratory depression, which [affects] breathing rate, and, in bad situations—especially when it's combined with things like opioid, benzodiazepines, even alcohol—that respiratory depression can be so severe that it leads to death. You just don't wake up. So those are the reasons why we think scheduling the drug is indicated here.

Alana Hippensteele: Right, absolutely. What led you and your colleagues to submit this petition to the DEA and FDA now?

Michael Abrams: Good question. [It’s] because gabapentin originally was approved for partial onset seizures back in 1993. Following that, a very similar drug, small molecule drug pregabalin, brand name Lyrica, was approved for some similar indications in 2005.

Pregabalin was scheduled and is still on schedule V. Gabapentin is not, going back to 1993. So why now? Well, after years of data, lots of publications, lots of what some people might call “real world data,” many observational studies, some clinical trials, and more precise clinical trial data, there's been increasing evidence of use and misuse of gabapentin and gabapentin enacarbil, and a clear demonstration that it has potential to be a substance of abuse.

Moreover, gabapentin, like the scheduled drug pregabalin, as I said, is clearly a powerful, small molecule that acts in the brain. But it's not well understood how it inhibits excitatory synaptic formation, their hypothesis about thrombospondin, and other pathways related to that—it's not really well understood. Why does it control seizures? Why is it useful for postherpetic neuralgia, another key indication for these kinds of drugs, that is the sort of neuropathic pain syndrome that follows the shingles outbreak, the shingles rash, it's useful and an on label for that. So, there's lots of evidence that it's being more widely used, more widely used for off label indications, specifically ones that are not approved, like post-surgical pain, like substance use disorder—somewhat ironically—these are off label indications [for which] the evidence base is weak.

Looking at the totality of the evidence, my senior colleagues of Public Citizen suggested that we do this petition—Dr. Mike Carome and Dr. Sidney Wolfe, both very experienced in these kinds of regulatory matters. We looked at the data and the publication record, which is vast, and crafted an application that we think demonstrates the key criteria that there's evidence of hazard related to this drug, it's widely used for indicated medical reasons, but it's also diverted by people for non-medical reasons. So those are all criteria that explicitly the DEA lays out and says, ‘These are the kinds of substances that we need to have authority over, and the ability to track and the ability to control and the ability to educate people about.’

So, that's why we feel that this petition is timely, and it took that period. There was only, in 2019, for example, that in the United Kingdom, both pregabalin and gabapentin were added to their schedule V, it's only been in the past few years, then in several states across the US, I think it's 7, that the states themselves have placed gabapentin on their local schedule. And then another 12 states haven't gone that far, but they have placed it on their prescription drug monitoring program list. So, states are already ahead. And certainly, the UK is ahead of where we think the US FDA, the world leader, supposedly, and the DEA, in terms of where drug regulation control should be.

Alana Hippensteele: Right, absolutely. How would the classification as schedule V change issues relating to gabapentin’s misuse, abuse, and potential for leading to overdose? So just further clarification here on how this will be impacted.

Michael Abrams: Yeah. So, here's the way I think of it. This is explicitly a gatekeeping, monitoring educational intervention, if you will. That's what we're proposing. You need to be able to, in order to, to deal with a problem that's in front of you, that concern about a substance being injurious to people, you need to be able to measure it and see it. That's part of what scheduling would allow.

That tracking happens would happen with regard to manufacturing, it would happen with regard to prescribing, and so there would just be data there. Moreover, a lot of the data that's encouraging us to do this initially comes from toxicology studies, and those are both clinical tox, right, looking at people who have overdosed and testing them, or people who have substance use problems testing to see if gabapentin is in their blood.

There's also, forensic tox, people who die, and you look at what's in their blood as well. And these studies have indicated that in certain regions when this has been done that gabapentin is evident. So that's a problem scheduling would promote further assessment of this. So that's one thing, sort of the monitoring piece is key.

The other key part is then actually the DEA prescribing to prescribers some cautions that they should have and some limits that they should have so that people aren't getting huge doses of gabapentin that could be so dangerous that, one pill might be an intentional or unintentional suicide action. And, moreover, just giving people so much excess medicine, that it's easier for them to be lured into the temptation of diverting it to others who might be seeking the gabapentin high exclusively, or as it turns out, there's clear at least qualitative evidence that gabapentin in combination with opioids, at least some people think, helps sort of promote that high.

Of course, we know from scientific studies, some even fairly straightforward controlled studies, that if you combine gabapentin and opioids, this respiratory depression threat is intensified, and that can be, as I said previously, a deadly combination, and that's what we're trying to get at here.