Number of units dispensed for dutasteride (red) and tamsulosin (blue) per 1,000 population per month in the United States from 2003 through 2007. The dutasteride campaign was associated with a greater increase in trend for tamsulosin units dispensed (0.76, 95 % CI: 0.02–1.50) than for dutasteride (0.45, 95 % CI: 0.33–0.56). The tamsulosin campaign was associated with an immediate increase in the number of tamsulosin units dispensed (5.76, 95 % CI: 1.79–9.72). Source: IMS Health National Prescription Audit™, January 2003–December 2007, IMS Health Incorporated.