Industry Money Fuels Gabapentin Prescribing

July 10, 2019

Pharmaceutical industry payments to doctors appear to have a strong influence over the prescribing of gabapentinoids, a class of pain medications with abuse potential, new research suggests.

Investigators found physicians who receive such payments are almost twice as likely to prescribe the more expensive brand-name gabapentinoids vs their generic counterparts.

"Our data show that physicians are being influenced by gifts from pharmaceutical companies. This is leading to unnecessarily high healthcare and patient expenditures on branded drugs," study investigator Taeho Rhee, PhD, University of Connecticut, Farmington, told Medscape Medical News.

"The relationship between doctors and the pharmaceutical industry has fueled the opioid crisis — the same thing could be happening with the gabapentinoid drugs. These drugs have been found to be addictive and associated with suicidal behavior and need to be prescribed very carefully," he added.

The study was published online July 8 in JAMA Internal Medicine.

$11.5 Million in Payments

Gabapentin (Neurontin, Pfizer) was approved by the US Food and Drug Administration (FDA) in 1993 for seizure disorders and postherpetic neuralgia.

The drug became available as a generic in 2004. Two extended-release versions are marketed as brand-name products. These include Gralise (Assertio Therapeutics) and Horizant (Arbor Pharmaceuticals). A related product, pregabalin (Lyrica, Pfizer), was approved in 2004 for seizure disorders, postherpetic neuralgia, neuropathic pain, and fibromyalgia. A generic formulation of pregabalin is not available.

The researchers report that use of gabapentinoids has increased from 1.2% of US adults in 2002 to 3.9% in 2015, raising concerns about appropriate use.

The investigators analyzed prescribing information for gabapentinoid products from the Centers for Medicare & Medicaid Services and Open Payments data documenting general (nonresearch) payments from industry to physicians.

Results showed that between 2014 and 2016, the manufacturers of the three brand-name gabapentinoids made 509,874 general payments ($11.5 million) to 51,005 physicians. These physicians represented 14.4% of doctors who prescribed any gabapentinoid product under Part D during these years.

Such payments were most commonly made to physicians in the southern and eastern regions of the United States. Generalist physicians received 62% of the payments and pain medication specialists 30%. Of the payments, 95% were for food and beverages, gifts, or educational materials.

Rhee and coauthor Joseph Ross, MD, Yale-New Haven Hospital, Connecticut, found that among physicians who prescribed any gabapentinoids, payments from the manufacturers of brand-name products were associated with a higher likelihood of prescribing these higher priced products as opposed to generic alternatives.

Physicians receiving payments from industry were more almost twice as likely to prescribe the three brand-name gabapentinoids compared with generic gabapentin (incidence rate ratio, 1.91; P < .001).

The authors note that brand-name gabapentinoids typically cost several hundred dollars for a 1-month supply. In comparison, generic gabapentin costs less than $20 per month. These brand-name products accounted for nearly $2500 in mean Medicare spending per beneficiary in 2016 compared with $89 for generic versions.

Need for More Regulation?

In an accompanying editorial, Robert Steinbrook, MD, JAMA Internal Medicine’s editor at large, points out that similar findings of increased prescribing from physicians who received drug company payments have been reported with opioids.

"All of these studies have essentially the same finding — that marketing to physicians is associated with increased sales of a company's product and increased Medicare expenditures," Steinbrook writes.

While he notes that association studies do not establish cause and effect, he adds, "the pattern is indisputable."

"Industry markets to physicians because physicians write the prescriptions. Marketing, however, can obscure the facts that generic medications are equally effective and usually much less expensive than brand-name medications. When there are choices, the generic alternatives should be prescribed," he writes.

"The many studies establishing the association between industry payments and physicians' prescribing of brand-name medications raise troubling questions about whether it is in patients' interests for physicians to accept these payments at all," he concludes.

High Off-Label Use

Commenting for Medscape Medical News, Michael L. Barnett, MD, assistant professor of health policy and management, Harvard T. H. Chan School of Public Health, Boston, said the study was very timely given the current policy debate over high drug prices.

"The results fit in with a broad literature showing that pharmaceutical marketing is effective at changing what physicians prescribe. It's no wonder that pharmaceutical manufacturers spend over $4 billion annually on 'detailing' of physician offices."

Barnett noted that there is also concern that gabapentin is extensively used off-label despite poor efficacy and that aggressive marketing may be partly driving its increasing use.

"What to do is a more challenging policy question," he said. "When clinically identical drugs exist, but one is much cheaper, laws like automatic generic substitution could make a big difference, as well as 'counter-detailing' to educate physicians about the benefits of prescribing generic medications."

Scott E. Hadland, MD, Boston University School of Medicine, added that this study adds to an ever-growing body of research showing that doctors who receive drug company marketing for specific medications prescribe those same medications at a much higher rate than other doctors.

"These data are concerning because they suggest that gabapentinoids are possibly being excessively prescribed in response to drug company marketing.

"Since, like opioids, gabapentinoids have the potential for misuse, we should be wary because the early years of the national overdose crisis were marked by excessive opioid prescribing," he said.

Hadland suggests that several states, including New Jersey and California, are looking into regulating drug-company marketing to physicians.

"But as it has been shown that multiple, inexpensive meals can be a highly effective marketing strategy to promote prescribing, any legislation should not only limit the total dollar value of marketing, but also the number of interactions that drug companies can have with a doctor," he says.

Pharma Companies Respond

Contacted for comment, a Pfizer spokesperson said: "Physician-industry interaction helps physicians stay up-to-date on their field and the medicines they prescribe. We do not pay health care professionals for prescribing our medicines or as an inducement for promoting our products."

Arbor Pharmaceuticals provided the following statement:

"Since our acquisition of Xenoport in mid-2016, Arbor Pharmaceuticals has marketed Horizant (gabapentin enacarbil) for the FDA-approved indications of moderate-to-severe primary restless leg syndrome (RLS) and post herpetic neuralgia.

"Generic gabapentin is not indicated for RLS. Horizant is clinically differentiated from other alpha-2 delta ligands as an extended-release prodrug with once-a-day dosing for RLS. Due to differing absorption and pharmacokinetic profiles, the FDA has determined that Horizant is not interchangeable with generic gabapentin. Therefore, Arbor has committed to responsibly educating providers on these key differences."

Rhee has disclosed no relevant financial relationships. Ross has reported research support through Yale University from Johnson & Johnson; Medtronic; the US FDA; the Blue Cross Blue Shield Association; the Centers for Medicare & Medicaid Services; the Agency for Healthcare Research and Quality; the National Heart, Lung, and Blood Institute; and the Laura and John Arnold Foundation.

JAMA Int Med. Published online July 8, 2019. Abstract, Editorial

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