Most free drug samples go to wealthy and insured patients, not to the poor and uninsured who may need them most, Harvard researchers report.

In fact, more than four-fifths of those who receive samples are insured, while less than one-fifth are uninsured and less than one-third have low incomes (below $37,000 for a family of four), the researchers found.

"Free drug samples influence prescribing and also introduce potential safety problems," said lead researcher Dr. Sarah Cutrona, a physician with the Cambridge Health Alliance and an instructor of medicine at the Harvard Medical School. "Despite these problems, many doctors support the program because [they say] free samples 'allow us to get free medications to our neediest patients,' " she said.

However, most free samples don't go to the neediest patients, Cutrona's group found.

In the study, Cutrona's team collected data on almost 33,000 people who participate in the annual Medical Expenditure Panel Survey. The researchers reported their findings in the February issue of the American Journal of Public Health.

The researchers found that the use of free drug samples is widespread, with more than 12 percent of Americans receiving one or more free drug samples in 2003. In addition, among those taking at least one prescription drug, 18.7 percent got free samples.

A study in the April 26, 2007, issue of the New England Journal of Medicine found that 78 percent of doctors received free drug samples and 94 percent had some relationship with pharmaceutical companies.

However, few free samples went to the needy, Cutrona and her colleagues found. In fact, those who received free samples were those with better access to medical care. Whites and people who spoke English were also more likely to receive free samples than members of ethnic, linguistic or racial minorities, according to the report.

In addition, getting medical care in an office rather than a clinic and taking more medications also increased the chances of receiving free drug samples.

Cutrona doesn't think that doctors deliberately ignore uninsured and poor patients when it comes to handing out samples, it's just that doctors in private practice are less likely to see the poor and uninsured.

Although drug companies tout drug sampling as a way to help needy patients, Cutrona disagrees. "These findings suggest that free samples serve as a marketing tool and not as a safety net," she said. "We need to examine whether free samples belong in our offices."

One expert contended that the study reveals the true marketing purposes of drug samples.

"It seems both the pharmaceutical industry and doctors share a Pollyanna view of free drug samples as a way of reducing costs for indigent patients," said Dr. David Katz, director of the Prevention Research Center at Yale University School of Medicine. "The reality, according to the data reported in this study, is quite different. The drugs are more likely to serve marketing than a 'safety net' function."

To serve as a real safety net, the use of free drug samples must be woven into the appropriate health care settings and situations, Katz said. "Otherwise, we have at best somewhat deceptive marketing, at worst, hypocrisy."

Reacting to the study, the Pharmaceutical Research and Manufacturers of America (PhRMA), an industry trade group, took issue with the findings.

"Instead of second-guessing motives, Harvard researchers would better serve patients by examining health outcomes," PhRMA Senior Vice President Ken Johnson said in a prepared statement. "Clearly, free samples often lead to improved quality of life for millions of Americans, regardless of their income."

"Unfortunately, many uninsured and underinsured patients do not receive their medical care from office-based practitioners," Johnson said. "As important as free pharmaceutical samples are in improving health care, they represent one -- not the only -- option for patients in need," he added.