Physicians who dispense sample medications may be more likely to write prescriptions for those drugs, Texas researchers reported here.

For seven out of eight physicians in a Texas clinic that accepted drug samples, there was a strong correlation between the number of samples distributed and the number of prescriptions written, Michael Averitt, D.O., and colleagues reported at a scientific meeting of the American Academy of Family Physicians.

The researchers analyzed prescriptions filled at three regional family practice clinics in the Scott and White healthcare system in Texas. Only one clinic, an office with eight doctors, accepted samples. “The influenza was present,” said Dr. Averitt, who is a Scott and White physician

Dr. Averitt and colleagues focused on the 25 most commonly used samples. Physicians in that clinic wrote significantly more prescriptions for those drugs than did physicians in the other two clinics (7,099 prescriptions for the samplers versus 6,044 and 5,727 for the non-samplers, p<.0001). The non-sample clinics had eight physicians in one group and seven in the other.

The total number of prescriptions written in each clinic during 2003 was 50,849 in the samples clinic and 50,686 and 42,907 in the no-samples groups.

Physicians in the samples clinic were also more likely to prescribe non-formulary drugs than those in the other clinics (p<.0001).

The average cost of a 30-day prescription was significantly higher in the sample-access clinic than in those without samples ($47.57 versus $39.49 and $41.48, p<.0001). These data, Dr. Averitt said, counter the frequent claim that sample medications decrease the overall drug costs to a healthcare system.

Scott and White recently instituted a policy by which clinics that accept samples have to keep logs of all drugs taken in and dispensed. Most clinics chose to discontinue accepting samples rather than add extra record keeping, the researchers said. However, two regional clinics, including the one studied here, continued to accept them.

Although it may not be possible to generalize the study results to the medical community as a whole, the study does indicate that pharmaceutical companies can influence prescribing habits by providing samples in at least some situations, Dr. Averitt said.

Although the patient populations are relatively similar in the three clinics, the average age of patients in the samples clinic was 41 versus 50 in the other two offices. Because physicians were all in the same healthcare system, they were exposed to the same education from the pharmacy and used the same formulary.

The Scott and White Foundation provided financial support for the study.