RALEIGH, N.C. – Offering free drug samples to newly diagnosed acne patients was found to increase the likelihood of prescribing more expensive medications, according to a new study.
"The benefits of free sample distribution in dermatology clinics must be weighed against the significant negative impact that free samples have on prescribing and prescription costs. Clinical trials comparing the efficacy of new branded generic drugs with existing alternatives should increasingly be used to justify their increased retail cost," said study investigator Michael Hurley, a Stanford (Calif.) University medical student.
The investigators analyzed all prescriptions written for newly diagnosed acne patients in 2010 at two dermatology clinics, one in an academic medical center that does not allow samples, and the second at an affiliated neighborhood clinic that does.
At the no-samples clinic, 17% of prescriptions written by office-based dermatologists for acne patients at their initial office visit were for branded or branded-generic drugs, compared with a 74% rate at the neighborhood clinic allowing free samples.
The average prescription costs were also higher at the clinic that uses free samples. The average retail cost of the top 20 prescribed acne medications at each site (which collectively accounted for roughly 70% of all acne prescriptions) was $204 at the neighborhood clinic, compared with $70.49 at the clinic with no free samples. After the average number of prescriptions written per visit was taken into account, this amounted to a cost difference of about $260 per office visit, reported Mr. Hurley.
In a multivariate regression analysis accounting for patient characteristics and other potential confounding factors, dermatologists who provided free samples of acne drugs were 3.4-fold more likely to prescribe a branded or branded generic drug than a less expensive generic.
After identifying the marked difference in dermatologists’ acne drug prescribing patterns at the two clinics in Northern California, Mr. Hurley and his coinvestigators analyzed national data to establish trends.
Data from the National Disease and Therapeutic Index – a national survey of physician self-reported office visits, diagnoses, and treatments conducted by IMS Health – were assessed. The data showed that in 2010, 79% of all prescriptions written by office-based dermatologists for acne patients at their initial visit were for branded or branded-generic drugs.
The data also found that the proportion of acne prescriptions written with a free sample increased from 38% to 51% in the last decade. Prescriptions for branded generic medications rose similarly, most likely because of the increased use of free samples of those drugs, said Mr. Hurley. Meanwhile the percentage of acne prescriptions for generic drugs has remained flat, and in absolute numbers has actually decreased, he said.
Upon close scrutiny of dermatologists’ acne prescribing nationally in 2010, 2005, and 2001, Mr. Hurley concluded that although dermatologists’ drug preferences do change over time as new medications enter the market, their prescribing consistently remains closely related to what’s available as a free sample.
For example, during 2010 the top five acne medications prescribed by dermatologists were (in descending order) Epiduo, doxycycline hyclate, Metrogel, Solodyn, and Differin. The top five prescribed with a free sample were Epiduo, Metrogel, Solodyn, Ziana, and Oracea.
The top five agents prescribed overall in 2005 were Differin, Benzaclin, Duac, Retin-A-Micro, and doxycycline hyclate, whereas the top five prescribed with a free sample during that year were Differin, Duac, Benzaclin, Retin-A-Micro, and Metrogel.
Mr. Hurley reported having no financial conflicts.