Several popular brand name drugs have just or are about become available in generic form as their patents expire, providing employers and employees an opportunity to save money on prescription medications.

"A prescription filled with a generic will cost — on average — about $40 less than a prescription filled with a brand-name drug. It is not uncommon to save 90 percent on the cost of a drug by going generic," says Cary Byrd, President of San Antonio, Texas-based eDrug.Search.com

"Every one percent increase in a plan sponsor's generic dispensing rate is equal to a one percent decrease in overall plan costs. It's very impactful," says Ritu Malhota, PharmD, with The Segal Company in Chicago.

Below are listed several high-profile drugs whose patents expired at the end of 2009 or will expire in 2010, a useful list when talking to PBMs or pharmacies. (Generic drugs are referred to by the lab name of their active ingredient. These are shown in parentheses.)

NOTE: Drug prices were from basic Part D plans offered by United Healthcare’s AARP MedicareRx Saver drug plan, to customers in area code 20852 (Rockville, Md.). Generic cost estimates came from non-U.S.-based on-line pharmacies and other sources. Dosages are omitted, but generic-brand name comparisons are for consistent dose amounts.

Lipitor (atorvastatin), the best-selling drug in the United States, is slated to lose patent protection in 2011, says Byrd. Best-selling anti-clotting agent Plavix (clopidogrel) will face generic competition in the United States in 2012.

For more information and strategies on health cost management, see Reducing Healthcare Costs for Employers from Thompson Publishing Group.