Amgen Inc. on Friday said that is recalling certain lots of its anemia drugs Epogen and Procrit because the vials could contain glass flakes.

The Thousand Oaks biotech said no problems have been reported, but if a patient injected contents of a contaminated vial it could cause blood clots, swelling of veins, immune system reactions and other problems.

The company said the flakes appear to be caused by an interaction of the drug with glass vials over the product’s shelf life. Affected lot numbers and expiration dates can be found on the products’ web sites, or patients can call 1-800-77-AMGEN for information.

Baxter International had a similar glass flaking problem earlier this year concerning its Hylenex rehydrating solution for children.

Epogen is used in the United States to treat anemia caused by kidney disease, and Procrit is a version it provides to Johnson & Johnson to treat chemotherapy-related anemia. Epogen was Amgen’s first drug and predecessor to the longer-lasting Aranesp, which created a scare a few years ago when experimentation with larger doses was found to increase the risk of stroke, heart attack and other life-threatening conditions.

Last year, Epogen sales totaled $2.65 billion for Amgen and Procrit sales were $2.25 billion for Johnson & Johnson.

Shares were up 44 cents, or less than a percent, to $56.16 in midday trading on the Nasdaq.