Free drug samples which physicians receive from pharmaceutical manufacturers and then hand on to their patients may actually prove more expensive in the long term for people without health insurance, a new study finds.

The availability of free samples, which are only available for brand-name drugs, greatly impacts on whether an uninsured patient is given a prescription for a generic or a brand-name drug, it says.

Researchers at Wake Forest University Baptist Medical Center in North Carolina tracked all prescriptions for antihypertensives, oral diabetic agents, peptic ulcer/gastroesophageal reflux medications and non-narcotic pain medicines written by more than 70 physicians for uninsured patients and those covered by Medicaid (the federal health care programme for people on low incomes) in the nine months up to and following the closing of their drug sample cabinet, which was due to the practice being relocated.

They found that, for the uninsured patients, the percentage of drugs prescribed as generics rose from 12% to 30% after the clinic closed its sample cabinet, but for the Medicaid patients there was no significant change in generic prescribing.

Throughout the study, Medicaid patients were generally prescribed generics, even with the availability of branded samples, and this surprised the researchers because at that time Medicaid did not operate a formulary, so all drugs for these patients, branded or generic, cost just $1.

One possible explanation is that because Medicaid patients rarely receive samples, doctors' prescribing decisions for them were based purely on what drug they thought was best and not on what samples happened to be available in the closet, said David Miller, lead researcher for the study.

Doctors frequently give their patients a drug sample initially in order to test tolerability and effectiveness, accompanying it with a prescription to fill after the sample is gone, and sometimes they use free samples to help patients who cannot afford medications, say the researchers, who publish their findings in the current issue of the Southern Medical Journal. However, they add, the availability of drug samples is not always predictable and, when patients return for refills and the samples they need are missing from a practice, either because the drug representative did not leave enough or stopped distributing them altogether, patients who were started on brand-name drugs in sample form are left paying the price when they have to fill a prescription.

"Physicians and medical organizations need to ask themselves if samples are doing more harm than good," commented Dr Miller. "While doctors might intend to help someone by handing them a free sample, in the long run, it could cost them more. And removing samples from a practice can help doctors focus on which medication is best for a patient, rather than which medication happens to be available for free."