Hikma, which makes anesthetics, pain medications, sedatives, neuromuscular agents and other drugs, announced the deal in September as a way for it to strengthen its injectable treatments unit in the United States. It was valued at $425 million at that time.

Under a deal struck with the FTC, Custopharm's parent company will retain assets related to the corticosteroid drug triamcinolone acetonide, or TCA, by shifting it to another subsidiary.

"Hikma's acquisition of Custopharm's TCA business could have caused significant harm for patients who use TCA to treat severe skin conditions, allergies, and inflammation," Holly Vedova, director of the FTC's Bureau of Competition, said in a statement.

(Reporting by Diane Bartz; Editing by Aurora Ellis)