The Effect of Competing Direct-to-Consumer Advertising Campaigns on the Use of Drugs for Benign Prostatic Hyperplasia: Time Series Analysis

Background: Direct-to-consumer advertising (DTCA) remains a controversial issue, with concerns that it leads to unnecessary and inappropriate prescribing. Whether DTCA shifts prescribing from first-line (guideline-recommended) therapy to second-line drugs has not been studied. Objective: The purpose of this study was to determine the impact of sequential DTCA campaigns for two drugs used to treat benign prostatic hyperplasia (BPH): one newer agent, dutasteride (Avodart^®), and one older first-line agent, tamsulosin (Flomax^®). Design: Interrupted time series analysis was used to assess the impact of each DTCA campaign using data on consumer “response” from Google Trends and dispensed prescriptions from IMS Health. Participants: We analyzed data for the United States from January 2003 to December 2007. Intervention: DTCA for dutasteride and tamsulosin commenced on July, 2005 and April, 2006, respectively. Main Measures: Monthly Internet search volume (scaled from 0 to 100) for the advertised trade name of each drug and monthly U.S. prescription rates per 1,000 population were analyzed. Key Results: The dutasteride campaign was associated with an increase in Internet searches for both “Avodart” (level change +31.3 %, 95 % CI: 27.2–35.4) and “Flomax” (level change +8.3 %, 95 % CI: 0.9–15.7), whereas the tamsulosin campaign was associated with increased “Flomax” searches (level change +25.3 %, 95 % CI: 18.7–31.8). The dutasteride campaign was associated with an increase in the prescription of dutasteride (trend = 0.45/month, 95 % CI: 0.33–0.56), but a larger impact was observed with tamsulosin prescriptions (trend = 0.76/month, 95 % CI: 0.02–1.50). Similarly, the tamsulosin campaign was associated with an immediate fourfold increase in the prescribing of tamsulosin (level change +5.76 units, 95 % CI: 1.79–9.72) compared to dutasteride (level change +1.47 units, 95 % CI: 0.79–2.14). Conclusions: DTCA was associated with the utilization of drugs to treat symptomatic BPH. However, both campaigns were associated with greater increases in the use of the guideline-recommended first-line agent. DTCA campaigns may increase the overall levels of guideline-recommended treatments to a greater extent than the specific advertised agents.