By Pat Anson, PNN Editor

Gabapentinoids – a class of nerve medication widely prescribed to treat chronic pain – increase the risk of suicide, overdose, traffic accidents and head or body injuries in younger people, according to a large new study published in The British Medical Journal.

Sales of the two main gabapentinoids, pregabalin (Lyrica) and gabapentin (Neurontin), have tripled in recent years in the United States, where they are often promoted in prescribing guidelines as safer alternatives to opioids.

A team of researchers followed nearly 192,000 people enrolled in the Swedish Prescribed Drug Register who filled prescriptions for gabapentinoids on at least two consecutive occasions from 2006 to 2013. That information was compared to data in the Swedish Patient Register, which collects information on hospital admissions and outpatient care, as well as the Swedish Cause of Death Register.

Over the study period, researchers found that patients taking gabapentinoids had higher rates of suicide or suicidal behavior (5.2%), unintentional overdose (8.9%), traffic accidents (6.3%) and head or body injuries (36.7%) than the general population.

The risks were strongest for people who were prescribed pregabalin and were most pronounced among adolescents and young adults aged 15 to 24.  Patients aged 55 and older taking gabapentinoids were not at greater risk.

Researchers believe the drugs may have more impact on younger people because they have faster metabolisms, which could lead to withdrawal problems that affect their impulsivity and emotions.

“Overall, gabapentinoids seem to be safe for a range of outcomes in older people. However, the increased risks found in adolescents and young adults prescribed gabapentinoids, particularly for suicidal behaviour and unintentional overdoses, warrant further research,” said lead author Seena Fazel, MD, of the University of Oxford in England.

“If our findings are triangulated with other forms of evidence, clinical guidelines may need review regarding prescriptions for young people, and those with substance use disorders. Further restrictions for off-label prescription may need consideration.”

Pregabalin is approved by the FDA to treat diabetic nerve pain, fibromyalgia, post-herpetic neuralgia caused by shingles and spinal cord injuries; while gabapentin is approved for epilepsy and post-herpetic neuralgia. Both drugs are also widely prescribed off-label to treat back pain, depression, migraine and other chronic conditions.

Gabapentinoids are increasingly being used recreationally by addicts who have found the medications enhance the effects of heroin and other opioids. The drugs were recently classified as controlled substances in the UK.

Gabapentin is not currently scheduled as a controlled substance by the DEA, while Lyrica is classified as a Schedule V controlled substance, meaning it has low potential for addiction and abuse.  

A recent clinical review found little evidence the drugs should be used off-label to treat pain and that prescribing guidelines often exaggerate their effectiveness. The CDC’s controversial opioid guideline, for example, calls gabapentin and pregabalin “first-line drugs” for neuropathic pain.

“Despite documentation that these drugs were promoted improperly for off-label treatment of pain, the recent rapid increase in prescribing of gabapentinoids suggests a persisting sense among clinicians that gabapentinoids are highly effective pain medications,” wrote Christopher Goodman, MD, and Allan Brett, MD, of the University of South Carolina School of Medicine.

“Guidelines and review articles have contributed to this perception by often uncritical extrapolation from FDA-approved indications to off-label use.”