By Pat Anson, PNN Editor

Despite warnings that they are overprescribed for conditions they were never intended to treat, the use of gabapentinoids continues to grow in the United States.

Pregabalin (Lyrica) and gabapentin (Neurontin) are both gabapentinoids, a class of nerve medication initially developed to treat epileptic seizures. Sales of Lyrica and Neurontin tripled a decade ago, when they were touted as safer alternatives to opioids and prescribed off-label for a variety of pain conditions.

In 2018, Michael Johansen, MD, a researcher and family medicine physician, was one of the first to warn that gabapentinoids were being overprescribed, despite little of evidence of their safety and efficacy for pain conditions. Johansen was particularly concerned the drugs were being given to older adults who were long-time users of opioids and benzodiazepines, a class of anti-anxiety medication.

Not much has changed, according to a new research study by Johansen. Using data from a large national survey, Johansen found that 4.7% of U.S. adults were prescribed a gabapentinoid in 2021, up from 4% in 2015 – a statistically significant increase of 17.5% in six years. The growth was primarily driven by gabapentin, as there was little change in pregabalin’s use.

As Johansen found in his earlier study, gabapetinoid use was much more likely in patients who were co-prescribed opioids, muscle relaxants, benzodiazepines or anti-depressants for chronic pain or mental health conditions. The likelihood of a patient being prescribed a gabapentinoid also rises sharply after age 50.

“Gabapentinoids continue to be commonly used in conjunction with other sedating medications, which is concerning in light of the US Food and Drug Administration’s 2019 warning about co-prescribing of gabapentinoids with other central nervous system depressants,” Johansen reported in the Annals of Family Medicine. “Gabapentinoids are likely used for an array of conditions, with the majority being off-label uses for chronic pain with minimal evidence supporting use.”

Despite those warnings, gabapentinoids — gabapentin in particular — are still being promoted as a treatment for all sorts of things, from dental pain to alcoholism to improving your sex life. Gabapentin has been pitched for so many different conditions that a drug company executive infamously called it “snake oil.”

Gabapentin is FDA-approved for epilepsy and neuropathic pain caused by shingles, but is often prescribed off-label for depression, ADHD, migraine, fibromyalgia, bipolar disorder and postoperative pain.  Pregabalin is approved for diabetic nerve pain, fibromyalgia, post-herpetic neuralgia caused by shingles and spinal cord injuries, but is also prescribed off-label for other types of pain.

Many patients report side-effects from gabapentinoids, such as weight gain, blurred vision, dizziness, sedation and cognitive issues. There are also an increasing number of reports that the drugs are being abused and sold on the street to boost the potency of illicit drugs.

“Reports of gabapentinoid abuse alone, and with opioids, have emerged and there are serious consequences of this co-use, including respiratory depression and increased risk of opioid overdose death,” Douglas Throckmorton, MD, a top FDA official said when the agency released  its 2019 warning.  

A 2019 study found little evidence that gabapentinoids should be used off-label to treat pain and said their effectiveness was often exaggerated by prescribing guidelines. The CDC’s 2016 opioid guideline recommended gabapentin and pregabalin dozens of times as alternatives to opioids, without saying a word about their abuse or side effects.

The CDC’s 2022 revised opioid guideline takes a more cautious approach, saying gabapentin and pregabalin can have “small to moderate improvements” on pain, but were associated with a moderate risk of adverse events. Evidence on their long-term use was also lacking, according to the CDC.