LOUISVILLE, Ky. -- A drug that has been touted as a safe alternative to opioid painkillers is now on the radar of health officials and law enforcement officials as it is being found in more and more overdose deaths. Gabapentin is a nerve pain medication that is typically used to treat seizures and pain associated with shingles. But amid the opioid epidemic that has ripped through the country, doctors have been prescribing it for a growing number of conditions in an attempt to find new ways to offer pain relief to patients -- and more people appear to be abusing it.

In Kentucky, lawmakers have classified the drug as a controlled substance after it was found in nearly one-fourth of all overdose deaths in the state's biggest city last year. As first reported in The Courier-Journal of Louisville, an analysis of coroner data discovered gabapentin was found in 93 of 407 fatal overdoses in Jefferson County, where Louisville is located.

Kentucky Office of Drug Control Policy executive director Van Ingram says gabapentin showed in roughly one-third of all drug deaths in 2016 across the state.

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In neighboring Ohio, police have also reported a significant rise in the abuse of gabapentin.

University of Louisville nursing school professor Rachel Vickers Smith says gabapentin isn't believed to be the cause of the local deaths, because more powerful drugs like heroin were detected as well, but gabapentin could have contributed. The drug is sold under the brand names Neurontin, Gralise, and Horizant.

A 2017 study of opioid users reported gabapentin and related drugs were easy to obtain and "reinforced the effects of heroin." Some users "were concerned it induced 'blackouts' and increased the risk of overdose," the researchers noted.

"Unfortunately, we now need to worry about it because people are abusing it," Dr. James Patrick Murphy, a pain and addiction specialist in Kentucky, told The Courier-Journal.

"Alone, it's not something that will stop your breathing or your heart," he said. "But if you take it along with a drug like heroin or fentanyl, together it might be enough to make you stop breathing and put you over the edge."

According to a paper published in August in the New England Journal of Medicine (NEJM), gabapentin was the 10th most commonly prescribed medication in the United States in 2016.

The authors, Christopher W. Goodman, M.D., and Allan S. Brett, M.D., of the University of South Carolina School of Medicine, note that while gabapentin has only been approved by the FDA for nerve pain, a growing number of doctors are "increasingly prescribing gabapentin… for almost any type of pain."

This is problematic for a number of reasons, they write, as studies show mixed results for gabapentin's effectiveness for off-label uses and side effects including sedation and dizziness.

The drug can also be dangerous if abused. "Some users describe euphoric effects, and patients can experience withdrawal when high doses are stopped abruptly," the authors write.

Goodman and Brett say that while patients in pain deserve empathy, doctors shouldn't assume that gabapentin is "an effective approach for most pain syndromes or a routinely appropriate substitute for opioids."

"Although gabapentinoids offer an alternative that is potentially safer than opioids (and presumably more effective in selected patients), additional research is needed to more clearly define their role in pain management," they write.