2018 has been a remarkable year for news and research into gabapentin, and the year is not even over yet! That is great news for those of us (myself included) who puzzle over the proper role of gabapentin within correctional medicine. On the one hand, if gabapentin is a useful drug for chronic pain, neuropathy, or any other medical condition, I want to use it properly. On the other hand, gabapentin is a ferociously abused drug within jails and prisons. It is both a sedating and euphoric drug that also can be hallucinogenic at high doses. When it is available within a prison, there is inevitably abuse of gabapentin (like snorting it), diversion of gabapentin (because it has large value within the correctional black market and so can be sold to others), and finally, there is inevitably coercion of weaker inmates by stronger inmates to acquire gabapentin prescriptions and give those prescriptions up to the strong.  Those of us in corrections have seen all of this and worse.

So any news of gabapentin, whether good or bad, can change the balance of this deliberation. If gabapentin is proven to be more effective medically, it may be worth tolerating the abuse. If it is found to be ineffective, there is no reason to introduce this stressor into the system.  With this in mind, here is a sample of the 2018 news on gabapentin.

First up is a speech (found here) given by Scott Gottleib, M.D., who is the Commissioner of Food and Drugs, on February 15, 2018, at the National Press Club in Washington DC. Dr. Gottlieb’s speech mainly addressed the opioid epidemic and the FDA’s role in combating opioid abuse. But besides opioid regulations, Dr. Gottlieb also discussed “gabapentinoids,” which include gabapentin and also pregabalin (Lyrica).

The data suggest that gabapentinoid misuse and abuse may be growing, both when taken alone and when taken with opioids, benzodiazepines or other central nervous system depressants. We’re concerned that the misuse and abuse of these drugs may result in serious adverse events.

Dr. Gottlieb went on to say that the FDA is investigating patterns of misuse of gabapentinoids and that “We’ll have more to say about our work on this challenge soon.”

It appears that what is obvious to us in correctional medicine—that gabapentin is a formidable drug of abuse—is finally being considered by the Washington regulators. All I have to say is: It’s about time! Articles about the abuse potential of gabapentin are showing up more and more, such as this great blog post, entitled Neurontin (Gabapentin)–The New Drug Threat You Didn’t Know About (found here). As a bonus, it has a great infographic!

Also this year, the Journal of the American Medical Associations (JAMA) published an important article entitled Gabapentin for Chronic Neuropathic Pain (found here). This was a meta-analysis of 37 randomized clinical trials that studied gabapentin prescribed for postherpetic neuralgia (PHN) and painful diabetic neuropathy (PDN). The conclusion was that gabapentin is effective for these conditions in some people. The number needed to treat (NNT) for one patient to experience substantial pain relief from PDN or PHN (depending on the study and the scoring scale) averaged around 8. On the flip side, the number needed to harm (NNH) with a significant side effect such as drowsiness, ataxia or dizziness was approximately 9. My interpretation of this data is that gabapentin does indeed help some patients with PDN—though most (around 7 out of 8) get no benefit compared to placebo. There is also a high incidence of side effects. Also, these conclusions only apply to post herpetic neuralgia and painful diabetic neuropathy. One might miss this important sentence on a quick reading:

Trials of patients with mixed neuropathic pain, phantom pain, radicular leg pain nerve injury pain and neuropathies related to human immunodeficiency . . . reported no difference between gabapentin and placebo.

An editorial accompanied the JAMA article that was entitled Gabapentin Approvals, Off-Label Use, and Lessons for Postmarketing Evaluation Efforts. (found here).
The main thrust of the editorial was that the marketing of gabapentin for conditions for which gabapentin did not have FDA approval was, to put it mildly, sketchy. This editorial is well worth reading. From a clinical perspective, however, this one sentence from the editorial is itself worth reading—twice!

Twenty-five years after the initial FDA approval of gabapentin, there is still limited evidence to support its widespread use for the majority of indications for which it is prescribed, many of which are off-label.

Gabapentin for Pain: New Evidence from Hidden Data (found here) is a great review from Therapeutics Initiative that summarizes both the gabapentin marketing shenanigans and the Cochrane data.

Finally, here are several more articles published this year concerning the efficacy of gabapentin:

Anticonvulsants in the treatment of low back pain and lumbar radicular pain: a systematic review and meta-analysis. (found here)

There is moderate- to high-quality evidence that anticonvulsants are ineffective for treatment of low back pain or lumbar radicular pain. There is high-quality evidence that gabapentinoids have a higher risk for adverse events.

Gabapentin for Off-Label Use: Evidence-Based or Cause for Concern? (found here)

With concerns for safety mounting, it is prudent to examine the efficacy of gabapentin across its many uses to understand the risk-benefit balance. Reviews on off-label indications such as migraine, fibromyalgia, mental illness, and substance dependence have found modest to no effect on relevant clinical outcomes. . . . Furthermore, the involvement of gabapentin in questionable marketing schemes further calls its use into question.

Benefits and safety of gabapentinoids in chronic low back pain: A systematic review and meta-analysis of randomized controlled trials. (found here)

Existing evidence on the use of gabapentinoids in CLBP (chronic low back pain) is limited and demonstrates significant risk of adverse effects without any demonstrated benefit. Given the lack of efficacy, risks, and costs associated, the use of gabapentinoids for CLBP merits caution.

As you can probably tell from this JailMedicine post, I myself am not a big fan of gabapentin, except in narrow circumstances.  This opinion is based on my training, my review of the literature and on my experience with the rampant abuse of gabapentin in both jails and prisons.  However, I could be wrong!