Almost half of sales visits by pharmaceutical company representatives advocating the use of the drug gabapentin led to doctors stating that they intended to increase their prescription of the drug or recommend it to colleagues, according to an analysis of a survey completed by the doctors shortly after the visits.
Nearly 40 percent of the visits involved discussion of so-called "off-label" uses of the drug not approved by the Food and Drug Administration, say the authors of the study.
At the time of the visits, gabapentin was approved only for secondary treatment of a certain form of epilepsy. Off-label uses included treatment of pain, migraine, and psychiatric conditions.
"The increased intention to prescribe after these sales visits is remarkable, and is in fact greater than has been observed in other studies," says lead author Michael A. Steinman, MD, a staff physician at the San Francisco VA Medical Center (SFVAMC).
The senior author is Lisa Bero, PhD, professor of clinical pharmacy and health policy studies at the University of California, San Francisco (UCSF) and an expert on pharmaceutical industry marketing practices.
The study appears in the April 24, 2007 issue of PLoS Medicine.
The authors analyzed a survey form that chronicled 116 visits to 97 physicians by pharmaceutical sales representatives from 1995 to 1999. The forms were collected by a market research firm and became available to the researchers as the result of a lawsuit against Parke-Davis, the maker of gabapentin. The lawsuit was brought by a former employee who alleged that the company promoted gabapentin, which it sold under the name Neurontin, for uses not officially approved by the FDA.
"To me, the remarkable thing is how effective a very brief visit by a drug representative most often less than five minutes can be in influencing physicians' choices to use a drug for an unapproved indication," Bero said.