Overlapping prescriptions of gabapentin and opioids grew over a 12-year period, pharmacy claims data showed.

Concurrent prescriptions increased from 1.9% in 2006 to 7.6% in 2018, a relative increase of 344%, reported Evan Peet, PhD, of the RAND Corporation in Washington, D.C., and co-authors, in a research letter published in JAMA Internal Medicine.

“As the opioid crisis continues throughout the country, clinicians are facing increasing restrictions on prescribing opioids,” Peet told MedPage Today.

“This study examines one way in which prescribers may be responding to these restrictions: prescribing gabapentin off-label concurrently with opioids,” Peet said.

“This approach to pain management has uncertain effectiveness and is potentially dangerous due to an association with all-cause and drug-related hospitalizations,” he pointed out.

Gabapentin is approved for seizures and post-herpetic neuralgia; gabapentin enacarbil is approved for restless legs syndrome. Despite limited indications, gabapentin and pregabalin (another gabapentinoid) are widely prescribed off-label for various other pain syndromes. Evidence is sparse for most off-label uses.

Common side effects of gabapentinoids include drowsiness, dizziness, blurry or double vision, and difficulty with coordination and concentration.

In 2019, the FDA warned about serious breathing problems that may occur in patients using gabapentin or pregabalin who have respiratory risk factors. These factors include taking opioids or other drugs that depress the central nervous system, having conditions like chronic obstructive pulmonary disease (COPD) that reduce lung function, and being older in age.

In their analysis, Peet and colleagues evaluated pharmacy claims data from 2006 to 2018 in IQVIA real-world longitudinal prescription records, which captured about 90% of prescriptions filled at retail pharmacies nationally.

The researchers defined opioid analgesic and gabapentin episodes by the first prescription fill date through the last day of the prescription’s supply. Subsequent prescriptions within 60 days of the prior one extended an episode by the amount of overlap, while prescriptions filled more than 60 days after the last prescription began a new episode.

In 2006, there were 37.4 million opioid episodes, which climbed to a high of 56.0 million before falling to 42.1 million in 2018. There were 1.5 million gabapentin episodes in 2006, which rose continually to 8.1 million in 2018.

Between 2006 and 2018, 18.1% of all overlap periods consisted of opioids and gabapentin episodes that began in the same week. By 2018, most overlap periods involved starting gabapentin before opioids.

Concurrent prescriptions were most commonly written by pain specialists (19.2% vs 4.2% for other specialties). “Differences between specialties may be exacerbated by cases in which gabapentin may have modest impact (e.g., chronic and/or neuropathic pain), by the complexity of cases overall, or because opioid prescribing restrictions more severely affect pain management strategies for complex cases,” Peet and colleagues observed.

Overlaps in prescribing occurred more among female patients, patients 66 and older, and patients who lived in rural, high-poverty, and predominantly white counties.

The findings suggested that increases in concurrent prescriptions might be an unintended consequence of opioid prescribing restrictions, the researchers noted.

The analysis looked at dispensed — not written — prescriptions, Peet and co-authors acknowledged. Data were limited to retail pharmacies only. In addition, the researchers did not have information about patients’ clinical status.