Amgen Inc is recalling several hundred lots of anemia drugs Epogen and Procrit, sold by Johnson & Johnson, because vials of the injectable medicines might develop tiny glass flakes that could cause blood clots and other serious health problems.

Amgen, which sells Epogen, manufactures the identical drugs at a plant in Puerto Rico.

Amgen spokeswoman Emma Hurley said the recall, which included 200 lots of Epogen, is not expected to disrupt availability of the drug and the biotechnology company does not expect a material financial impact.

J&J spokeswoman Lisa Vaga said 155 lots of Procrit were recalled, but declined to comment on any financial impact to the company.

Amgen said there have been no patient complaints that can be directly attributed to the presence of glass. It said the lots were being voluntarily recalled as a precaution.

The glass flakes result from the interaction of the drug with glass vials over the shelf life of the product, the company said.

Hurley said expiration dates for the drugs have been reduced to 12 months for single-dose vials and 15 months for multi-dose vials. Their shelf life had been 36 months.

She also said the company would switch vial manufacturers.

From an investor standpoint, I don't think there's any real impact at all, said Cowen & Co analyst Eric Schmidt. There's no patient safety issue, no one's been harmed here. There's no supply issue. There will be plenty of supply to go around.

Amgen sells Epogen in the United States, where it is used mostly for kidney dialysis patients. Under a long-standing license from Amgen, J&J's Centocor Ortho Biotech unit distributes Procrit in the United States, mainly for cancer and HIV patients. J&J has been dealing with a rash of recalls of its consumer medicines.

Biotechnology company Genzyme Corp has had its reputation damaged by product shortages caused by manufacturing quality control issues.

Since the Amgen recall relates to materials rather than production processes, the impact on the company will be much more limited, said Bernstein & Co analyst Geoffrey Porges.

Amgen said the recall is being conducted in cooperation with the U.S. Food and Drug Administration.

Amgen's 2009 sales of Epogen totaled $2.6 billion, while J&J's Procrit sales were $2.2 billion over the same period.

Both medicines are engineered antibodies that work by stimulating production of red blood cells.

Amgen shares were up 0.7 percent in afternoon trading at $56.11. J&J shares were up 0.3 percent at $61.99.