The FDA slapped Hospira with a warning letter over conditions at a manufacturing plant in Italy.
The March 31 letter is the fifth one lodged against the company within the past two years, bringing the total to seven since 2010, the Associated Press reported.
The warning letter described shortcomings such as a failure to show the plant has implemented measures to prevent product contamination and repeats of violations the FDA addressed during a 2012 inspection of a Hospira plant in India.
The AP said Hospira has taken $450 million in charges related to problems cited in the series of FDA letters it has received.
Pfizer agreed to buy Hospira in February for $17 billion. The deal is expected to close later this year.
