Brand-name versions of a pain drug – gabapentin – are reportedly being prescribed in favour of pharmaceutical companies’ payments to doctors, according to research by a team from Yale University in Connecticut, US.

Gabapentin is usually prescribed by pain doctors or general practitioners to control seizures and treat nerve pain. Chemically similar to the brain chemical gamma-aminobutyric acid (GABA), gabapentin works by calming overexcited brain cells, and does not interact dangerously with other drugs.

But gabapentin use has increased three-fold in the US between 2002 and 2015, as observed from prescription records which analogues rises from 1.2% of adults in 2002 to 3.9% of adults in 2015. Greg Rhee, an Assistant Professor of Medicine at the University of Connecticut Health Center (UConn Health) wanted to understand why.

Rhee and colleagues wondered if payments from the pharmaceutical industry to doctors might be influencing prescription, and so, analysed Open Payments and Medicare Prescriber databases between 2014-2016. Both databases are made available through the Centers for Medicare and Medicaid Services – Open Payments is a national program that obligates drug manufacturers to disclose payments made to physicians, while the Medicare Prescriber database shows all prescriptions made to people in Medicare plans, searchable by doctor/drug.

Surprisingly, the more physicians received industry money, the more likely they were to prescribe expensive, brand-name gabapentin. About 14% of the doctors who received payments from gabapentin manufacturers – overall US$11.5 million, to be exact – were likely to do this, instead of prescribing the generic supply available. Most of these doctors were located in the southern and eastern parts of the US.

Besides cost, the rise in prescriptions also points to drug abuse – although gabapentin is not reported to be intoxicating, taking the drug in large quantities can cause a long-lasting high. Even some long-term users, who took gabapentin at therapeutic doses, report it can be addictive.

Rhee and his colleagues are concerned that gabapentin may be diverted for recreational purposes in light of the increased prescriptions, but admit that more research is needed for a conclusive stance on the matter.