Did drug reps encourage doctors to prescribe gabapentin for nonapproved uses?

Apr 25 2007

A new study published in PLoS Medicine suggests that so-called "detail" visits to doctors made by drug company representatives can involve promotion of drugs for non-approved, "off-label" uses.

This may subsequently result in increased prescribing of the drugs for such purposes. Michael Steinman and colleagues from the University of California, San Francisco based their study on visits to doctors made by representatives of the company Parke-Davis between 1995 and 1998 to promote the drug gabapentin.

In the USA, before a company can market a drug to doctors for a specific "indication" (i.e. the treatment for a particular condition and group of patients), it has to be approved as safe and effective for that use by a government agency, the Food and Drug Administration. Once a drug is approved, doctors are allowed to use it for whatever non-approved indications they think are appropriate, but the drug company cannot actively promote the drug for anything other than its approved use. There have been concerns that companies indirectly try to promote use of drugs for indications that are not approved. One tactic that companies use to sell drugs is "detailing". Detailing involves direct visits from company representatives to individual doctors. However, not a great deal is known about detail visits and the effect that they have on doctors' behaviour.

Steinman and colleagues took advantage of an opportunity for researching detailing that came about as a result of a lawsuit, during which drug company documents were subpoenaed ? i.e. required by the court to be made available. In that lawsuit, it was alleged that Parke-Davis had promoted gabapentin for many non-approved uses. (The company that subsequently took over Parke-Davis eventually made an out-of-court settlement.) During the relevant period of time, the only approved use of gabapentin was for treatment of partial seizures in adults with epilepsy, in combination with other drugs. However, gabapentin was used for many other conditions such as treatment of psychiatric disorders and management of pain. These researchers used the documents to research detailing and the impact it had on doctors' attitudes towards gabapentin.

The documents had been produced by a market research company, which had asked doctors visited by Parke-Davis representatives to fill out a standard form after each visit. The researchers focused on data relating to visits made by a single representative to a doctor or small group of doctors, and collected 116 forms. The researchers classified the information available from the forms, identifying whether the "main message" related to approved uses of the drug or not; and extracting data relating to whether doctors planned to increase, maintain, or lower, their use of the drug. The majority of the visits studied were to doctors who were not neurologists, so who would be unlikely to be prescribing gabapentin for its approved use. Doctors reported that a substantial proportion of the detail visits contained messages relating to non-approved uses of gabapentin. Although the majority of visits lasted 5 minutes or less, nearly half the doctors stated in the forms that their use of gabapentin would increase in the future, and no doctor said that their use would decrease following the visit. Doctors' stated intention to increase their use of gabapentin was similar whether the main message involved approved or unapproved uses of the drug. In addition, doctors' stated intention to increase their use of the drug was also similar whether the visit was of higher or lower educational value, or of shorter or longer duration.

This research does not establish whether similar activities take place regarding other drugs and drug companies.