Patent expirations on big-name drugs such as Lipitor and Plavix has resulted in modestly less spending on medicines in the U.S. for the first time in at least 55 years, according to a report released on Thursday.

Overall U.S. spending on medicines totaled $325.8 billion in 2012, down 1 percent from 2011, according to the report from the IMS Institute of Healthcare Informatics. Adjusting for population, per capita spending fell 3.5 percent to $898.