By Pat Anson, PNN Editor

It’s become trendy in recent years for U.S. hospitals to use gabapentin (Neurontin) as a “safer” alternative to opioids for post-operative pain.  But a large new study has found that gabapentin increases the risk of delirium and other adverse health effects in older patients recovering from surgery.

The study, published in JAMA Internal Medicine, looked at nearly a million patients over the age of 65 who had major surgical procedures, including cardiac, orthopedic and gastrointestinal surgeries. About 12% of the patients received gabapentin and other analgesics for perioperative pain management between the day of surgery and two days after surgery.

Researchers found that gabapentin “modestly increased” the risk of delirium, a mental state in which a person becomes confused, disoriented and unable to think or remember clearly. Patients who received gabapentin were also more likely to be prescribed antidepressants and other anti-psychotic drugs, and to develop pneumonia.

“Considering the increasing number of major surgeries performed in older adults, and the negative consequences of perioperative delirium, our findings raise concern about an increasingly adopted clinical practice that involves routine use of gabapentin as part of multimodal analgesia,” wrote lead author Dae Hyun Kim, MD, a geriatrician and epidemiologist at Brigham and Women's Hospital and Assistant Professor of Medicine at Harvard Medical School.

“On the basis of these findings and those of meta-analyses of RCTs (randomized controlled trials) showing a weak opioid-sparing effect of gabapentin, clinicians should reconsider routine use of gabapentin for perioperative pain management among older adults and individualize the treatment decision after assessing the risk of immediate harms vs opioid-sparing benefits of perioperative gabapentin use.”

‘Windfall Medication’

Although gabapentin is an anti-convulsant that was originally developed to treat epilepsy, it is increasingly prescribed “off-label” to treat various types of pain. In 2016, the American Pain Society recommended that gabapentin be used “around the clock” for post-operative pain because it lowered pain scores and reduced the use of opioids. But studies later found the drug was ineffective for post-operative pain and actually increased the risk of an overdose.

An editorial published in JAMA Internal Medicine said the new study demonstrates that the risks of gabapentin outweigh its potential benefits in older patients.

“These results are consistent with what is now a growing body of literature suggesting that gabapentin may not be the windfall medication for perioperative pain management that surgeons hoped it might be for decreasing opioid use. The adverse events reported in this study (delirium, antipsychotic use, and pneumonia) add to similar findings that gabapentin, especially when used concomitantly with opioids, increases the risk of postoperative sedation and dizziness,” wrote lead author Zachary Marcum, PharmD, University of Washington School of Pharmacy.  

“As the use of gabapentin continues to rise, it is critically important clinicians understand its risks, especially for older adults. Poorly controlled postoperative pain is associated with several complications, including cognitive impairment, delirium, depression, decreased mobility, and longer recovery.”

It’s a common misconception that patients often become addicted to opioids after surgery. A 2016 Canadian study found that long term opioid use after surgery is rare, with only 0.4% of older adults still taking opioids a year after major elective surgery. A 2018 study at Harvard Medical School had similar findings. Only 0.6% of patients who were prescribed opioids for post-operative pain were later diagnosed with opioid dependence, abuse or a non-fatal overdose.