Spending on direct advertising of prescription drugs to the public is growing rapidly, reaching $2.47 billion in 2000. Pharmaceutical companies are requesting further relaxation of advertising restrictions in the United States, Canada, and other countries, in hopes that increased public information will lead to greater use of prescription medications. Mintzes and colleagues studied the effect of direct-to-consumer advertising on the prescribing practices of physicians.

The authors surveyed patients who attended primary care practices in Sacramento and Vancouver on selected days. About 60 percent of all eligible adults who attended the practices of 78 physicians on the selected days participated in the study. The patients generally had above-average income, and 80 percent were of European descent.

In 12 percent of the 1,431 visits, patients requested prescriptions. Of these requests, 42 percent concerned products that had been directly advertised to the public. Patients who requested a prescription were more likely to receive one, but the prescribing rate was nearly the same for advertised and nonadvertised drugs. Physicians were asked if they would prescribe similarly for another patient with the same condition who did not request the drug. Physicians reported ambivalence about treatment in about 40 percent of cases when the patient requested drugs, compared with 12 percent of cases when the patient did not make such a request. When the patient specifically asked for an advertised drug, physician ambivalence increased to 50 percent.

The authors conclude that a patient's request for drugs is a powerful factor in prescribing practices. Although physicians generally prescribe the requested medication, they feel ambivalent about this choice of treatment. The direct advertising appears to increase sales of drugs but may have an adverse effect on appropriate prescribing practices.